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AbstractA metal-organic framework, UiO-66, has been evaluated as adsorbent in a post-combustion vacuum swing adsorption (VSA) process. Equilibrium isotherms of the most relevant gases (CO2 and N2) as well as breakthrough curves measured using synthetic flue gas containing 15 mol% CO2 without and with 9 mol% water vapor are reported. Based on the breakthrough data, a six step one-column VSA cycle is designed and the effects of adsorption and CO2 rinse times used on the CO2 recovery and CO2 purity are examined. With the chosen process configuration and cycle design CO2 purities around 60% and CO2 recoveries up to 70% are achieved. 50 cycle adsorption-desorption experiments show that the cyclic CO2 capacity is reduced by approximately 25% in the presence of water vapor. No reduction in cyclic capacity is observed with increased cycle number; there is rather a slight increase in cyclic capacity with cycle number indicating that a cyclic steady state still not has been reached after 50 cycles.

AbstractThe effect of heat distribution or inter-heating on the total energy requirement for CO2 stripping is investigated. Here we look at retrofit design of an existing column. It means the height and diameter of the stripper is given. The results show that inter-heating can have both negative and positive effects on the total energy requirement. If only one heat source at constant temperature exist, the inter-heating will increase the total energy requirement. If there are other heat sources at different temperatures, inter-heating can be beneficial. It depends on the energy price of the different heat sources and the temperature profile of the column. If there are some hot streams available to utilize the heat in the inter-heater, the total energy requirement will decrease. As a case study utilizing heat from lean amine in the inter-heater is investigated. The simulation results show a saving up to 6.4 and 11.3 percent by one and two inter–heater respectively

AbstractDuring the last decades significant effort has been put into research on the social, economical, political and technical issues related to large scale deployment of Carbon Capture and Storage (CCS). A complete CCS cycle requires safe, reliable and cost efficient solutions for transmission of CO2 from the capturing facility to the location of permanent storage. The current initiative originates from DNV’s long engagement in developing standards and guidelines for offshore pipelines and an identified need to specifically address the technical challenges related to transmission of CO2 with associated contaminants. The guideline will be based on a comprehensive literature review and gathering of experience from existing (both onshore and offshore) CO2 pipeline operators. Available pipeline codes, standards, guidelines and regulations combined with the latest available research and technical developments is set as the point of departure for this guideline development. Issues related to pipeline design, commissioning and operation as well as re-qualification/conversion of existing pipelines for transmission of CO2 will be addressed. The guideline is being developed as a joint industry project and is scheduled for delivery by end of July 2009. After completion of the JIP, the guideline will be converted into a public available Recommended Practice (RP) by Det Norske Veritas (DNV). The guideline will give “how to?” answers for safe, reliable and cost-effective transmission of CO2 in pipelines. This paper addresses main technical issues one need to manage.

AbstractAn absorption and desorption rig has been in operation at Telemark University College since 2010. The purpose of the rig is to perform measurements of CO2 removal efficiency and heat consumption at different process conditions like temperatures, flows and CO2 concentrations in the gas and the liquid. 30 wt-% monoethanolamine (MEA) in water has been the most used solvent. In earlier work, the heat consumption has been indirectly measured by the electricity consumption for steam production. In this work new results from 2012 and 2013 are presented where the steam consumption has been measured directly by a vortex flow meter.

AbstractFor a commercial Carbon Capture and Storage (CCS) chain to be successful, it must satisfy a whole range of requirements: technical, economic, environmental, safety, and societal. A comprehensive, understandable and reproducible assessment of CCS projects is a complex task due to several reasons: wide range of actors and factors involved, substantial differences in the type and nature of both actors and factors, and numerous associated uncertainties. In this paper, a standardised methodology is described and illustrated on a few examples of relatively simple case studies. The proposed methodology provides means and tools for evaluation of several economic, environmental, and in the future also risk associated criteria and thereby enables selection of the most promising options for CCS. The methodology will also help to reduce the uncertainty by improving understanding of the most important dependencies and trends for the investigated key performance indicators as enlightened by the case studies examples. It could also help to design efficient incentives and measures to stimulate realization of CCS by identifying and evaluating the most important non-technical factors affecting the CCS chain viability.

This paper studies the impact that different approaches of modeling the real-time use of the secondary regulation reserves have in the joint energy and reserve hourly scheduling of a price-taker pumped-storage hydropower plant. The unexpected imbalance costs due to the error between the forecasted real-time use of the reserves and the actual value are also studied and evaluated for the different approaches. The proposed methodology is applied to a daily-cycle and closed-loop pumped-storage hydropower plant. Preliminary results show that the deviations in the water volume at the end of the day are important when the percentage of the real-time use of reserves is unknown in advance, and also that the total income in all approaches after correcting these deviations is significantly lower than the maximum theoretical income.

AbstractThis work examines the dynamic response of a single semi-submersible wind turbine (SSWT) based on different hydrodynamic theories. Comparisons of platform motions and structural responses in the wind turbine are shown for simulations for a model with linear potential flow solution and quadratic drag and simulations with only Morison-type forces. The SSWT modelled in this study is based on WindFloat and carries the NREL 5MW wind turbine and should be considered a large volume structure. This implies that diffraction effects should be considered by using potential flow theory and viscous effects by Morison's equation.A new coupled simulation code was developed by linking the SIMO and RIFLEX hydrodynamic, structural, and control system computational tools, from MARINTEK, with the aerodynamic forces and wind field generation capabili–ties of AeroDyn and TurbSim, from NREL. In contrast to other available simulation codes, this combination enabled the implementation of these two different hydrodynamic theories and offered the possibility of finite element mooring line models. Wave-only simulations were considered first, in order to tune and compare potential theory versus the inertia term in Morison's equation. Some limited coupled wave-wind simulations give an indication of the extent to which hydrodynamic modelling affects the global response.The SSWT case study showed that the Morison model with forces integrated up to wave elevation gave a good representation of the motions compared to the potential flow model with quadratic drag forces. It also showed that mo–tions are sensitive to choice of added mass coefficients, stretching and dynamic pressure under the columns. Combined wind and wave simulations, using a non-optimized control approach, showed that pitch motions influence the power production and blade bending moments.

AbstractOffshore power systems will be characterized by a large penetration of power electronics converters and power cables, resulting in complex behaviors that can be quite different from traditional AC systems. Analyzing such systems is challenging due to their complexity and the relative lack of experience. In this context, performing laboratory tests in scaled down model network have significant relevance to verify simulation models and to test equipment and control methods in a controlled environment. The design of the laboratory needs to be a compromise between the capability to accurately reproduce the real system behavior and the practical constraints on ease of use, equipment size, cost and safety. This paper summarizes the main design considerations for a laboratory infrastructure dedicated to research of future offshore grids and the possible challenges. The laboratory facility developed jointly by NTNU (Norwegian University of Science and Technology) and SINTEF Energy Research is described with examples of the experimental possibilities.