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Abstract: Extensive investment into research and development of low emission coal technologies is occurring around the globe. However, surveys suggest that most members of the general public are unaware of advanced coal technologies like carbon dioxide capture and storage (CCS). Further, those people who are aware of the term tend to have little understanding of the concept. This lack of awareness has become an increasing focus of policy makers internationally, and a number of governments have developed communication strategies to raise awareness of CCS and other low emission coal technologies and to help promote social acceptance of these technologies. The present research synthesizes the range of communication activities that have been planned or implemented since 2002 in Australia and internationally, and examines the strengths and weaknesses of these activities. The resulting “roadmap” enables interested parties to draw from the best communication processes available, to help increase capability in this area for the ultimate successful deployment of CCS. The paper makes a number of recommendations for industry and policy makers to provide a guide for future communication strategies regarding CCS. [Copyright &y& Elsevier]

Abstract: This paper reviews the use of a large group process for engaging the public on energy sources and technologies with a low emission profile. Specifically reported in this paper is how the large group process supports exploring Australian society’s acceptance of energy technologies by examining the effectiveness of the process for informing knowledge and changing attitudes towards low emission energy technologies. Carbon dioxide capture and storage (CCS) is given further attention in the paper because, as a relatively unknown technology with perceived risks, it is useful to examine the effects of information provision on the way the technology is perceived. Given the large group process has proven to be a successful method for accessing and informing larger numbers of stakeholders, it is one recommended to policy makers and other researchers with an interest in low emission energy technologies. [Copyright &y& Elsevier]

Abstract: This paper presents the results of a collaborative project on public acceptance of Carbon Capture and Storage (CCS) in Germany, commissioned by the German Federal Ministry of Economics and Technology (BMWi). The project “Socio-economic Research on Acceptance of CCS” (April 2006 to March 2008) analyzed various aspects of public acceptance of CCS mainly in the national context of Germany. It was the first project to handle this subject matter. Public acceptance is one of the crucial factors for the implementation of CCS in the future. [Copyright &y& Elsevier]

Abstract: Recent surveys, polls, and other research focused on stakeholder attitudes towards the nascent commercial deployment of carbon dioxide capture and storage (CCS) technologies revealed that the general public knows relatively little about CCS. Given this lack of knowledge with respect to the concept of CCS—let alone first-hand experiential knowledge derived from seeing these technologies deployed in local communities—it is imperative to re-examine how research on CCS stakeholder involvement is conducted and how the results of these studies are reported. This paper will explore several such framing issues regarding future stakeholder involvement activities. [Copyright &y& Elsevier]

Abstract: A public survey was conducted concerning carbon capture and storage technology (CCS) in the months of February and April 2007 in Japan, Previously another CCS survey took place in December 2003, and a set of the questions asked in the 2007 survey were purposely the same as that used in the 2003 survey, Japanese adults were randomly selected to answer a questionnaire either in printed format or in online format. Several versions of the questionnaire were used, and each contained a different educational part, imparting relevant CCS information. 334 people successfully responded to our paper survey in Tokyo and Sapporo while 2156 people completed our online survey across the nation. The questionnaire for the survey contained 5 sets of different information package on CCS and questions asking pros and cons on CCS implementation to analyze influence of information provided on CCS. Based on the results of survey we found: that not many people still know about CCS. Those who have knowledge on CCS show a preference for CCS implementation, however; preference was decreased after obtaining information which we considered was neutral on CCS. These results suggest a possibility that information on negative aspects of CCS (risks, etc.) would not be well known in the general public. We also found that preference for CSS decreased slightly after providing different information on CCS to respondents in the group with the newspaper articles which we considered neutral in comparison with other groups. The newspaper articles contained the information on negative opinions against CCS besides risk-related information as well as information based on an IPCC Special Report: it is assumed that such negative opinions may have influenced opinion formation of respondents. Since CCS is new technology, information about how other people or entities evaluate CCS would influence public opinion. In the sub-sample provided with industrial and natural analogues of preference on geological storage, the views were slightly more positive about CSS in comparison with reported opinions of other groups. This implies information on natural or industrial analogue would help manage perception of risk in a positive way. The result of path analysis to data of a public survey identified four factors, (1) risks and leakage, (2) effectiveness of CCS, (3) responsibility, and (4) fossil fuel use. We found that the factor of understanding the effectiveness of CCS is most positively influential for general acceptance of CCS. I Implementation of geological storage and the factor of risks and leakage become much more influential negatively in the implementation of geological storage compared to general acceptance of CCS, implying that implementation of CC2 geological storage also needs careful communication of risk. [Copyright &y& Elsevier]

Abstract: The importance of public acceptance of CCS has been highlighted by developers and policy makers, with all emphasising that it is a fundamental factor in the future success of CCS. However, little research has been done so far on NGO positioning on CCS. The current debate in Europe, with discussion beginning to result in both real projects on the ground and in real policies, has put NGOs more and more into a position of making open stands. This has resulted in a diversity of viewpoints, and the controv ersy has polarized opinions. In this paper we review our own research on NGO opinions on CCS, to spell out their most important concerns. We discuss NGO positioning vis-à-vis the ongoing negotiations of a legislative proposal to regulate CCS in Europe. Finally, we consider whether it is possible to come to more coherent approaches and agreements in a way that maximizes their effectiveness both as a counterweight to, and partner of, other stakeholders and governments. [Copyright &y& Elsevier]

Abstract: This paper presents results from a survey on stakeholder attitudes towards Carbon Capture and Storage (CCS). The survey is the first to make a global comparison across three major regions; USA, Japan, and Europe. The 30-question survey targeted individuals working at stakeholder organizations that seek to shape, and will need to respond to, policy on CCS, including electric utilities, oil & gas companies, CO2-intensive industries and non-governmental organizations (NGOs). The results show generally small differences across the regions and between the different groups of stakeholders. All believed that the challenge of significant reductions in emissions using only current technologies was severe. There is a widespread belief both that renewable technologies such as solar power and CCS will achieve major market entry into the electricity sector within the next 10 to 20 years, whereas there is more skepticism about the role of hydrogen and especially nuclear fusion in the next 50 years. All groups were generally positive towards renewable energy. Yet, there were some notable areas of disagreement in the responses, for example, as expected, NGOs considered the threat of climate change to be more serious than the other groups. North Americans respondents were more likely to downplay the threat compared to those of the other regions. The Japanese were more concerned about the burden that would be placed on industry in the coming decade as a result of emissions constraints and NGOs were more likely to believe that the burden would be light or very light. NGOs believed CCS to be far more attractive than nuclear fusion power but much less than renewables. As expected, the risk for leakage from reservoirs was ranked number one of the risk options given. [Copyright &y& Elsevier]

Abstract: This paper analyses and compares the results of accelerated carbonation experiments for CO2 storage carried out on the air pollution control (APC) residues of a waste incineration plant, via both the dry and the wet route. The two routes achieved a similar maximum calcium conversion to carbonates (around 65%) corresponding to a potential CO2 storage capacity of 250 g/kg residues. For the dry route, maximum conversion was achieved in a few minutes at 400 ∘C under a 10% CO2 atmosphere, whereas for the wet route it was obtained in about 10 minutes under a 100% CO2 atmosphere, with a liquid to solid ratio of 0.2, at 30 ∘C and 3 bar, or without water addition at 50 ∘C. These results suggest that carbonation of APC residues, and possibly of other combustion residues, through either the dry or wet route, may be effectively applied for CO2 storage, at least in the niche market of waste incineration. [Copyright &y& Elsevier]

Abstract: The current low-cost process for mineral carbonation involves the direct carbonation of a slurry of magnesium or calcium silicate mineral with supercritical CO2. The process is currently limited by the slow reaction kinetics of the carbonation reactions, and in particular the slow dissolution rates of the silicates in weakly acidic conditions. Enhancing the dissolution rate in weakly acidic conditions has been identified as one of the main opportunities for lowering the costs of a direct mineral carbonation process. Serpentine has been identified by its reactivity and abundance as a potential mineral for use in a mineral carbonation process. In this paper we discuss the results of dissolution experiments in which ground serpentine was reacted in weakly acidic aqueous systems containing NH4Cl, NaCl,, sodium citrate, sodium EDTA, sodium oxalate, and sodium acetate. All experiments are carried out at 120 ∘C and under 20 bars of CO2 in a batch autoclave. It was found that the sodium salts of citrate, oxalate, and EDTA significantly enhance the dissolution of serpentine under weakly acidic conditions. [Copyright &y& Elsevier]

Abstract: The ashes from lignite combustion are characterized by high CaO and free CaO contents and are a potentially interesting material for CO2 bonding, more particularly as theirs economical use is limited. The findings of CO2 absorption by suspensions prepared on the basis of ash from lignite combustion are presented in the paper. On these grounds CO2 sequestration potential via mineral carbonation in ash aqueous suspensions in Poland will be estimated. [Copyright &y& Elsevier]

Abstract: The most promising route for mineral carbonation is the aqueous process using naturally occurring silicate minerals. The overall carbonation reaction consists of the dissolution of MgO- or CaO-bearing silicates such as olivine, serpentine, and wollastonite, followed by the precipitation of carbonates such as magnesite and calcite. In this paper, we report the experiments to investigate both the dissolution and the precipitation processes, separately. Olivine dissolution kinetics has been studied under several temperature and CO2 pressure, and by varying the solution composition. The experiments were performed in a flow-through reactor at 90–120–150 ∘C. The pH was adjusted using either acids (e.g., HCl, citric acid) or LiOH, and by changing the CO2 pressure while the salinity was varied by adding NaCl and NaNO3. To estimate the dissolution rate for each experiment, a population balance equation (PBE) model coupled with a mass balance was applied. The obtained values were regressed over a pH range from 2 to 8, using a linear model of the form , where is the specific dissolution rate (mol cm−2 s−1). The experiments to study the kinetics of magnesite precipitation were performed in batch using the H2O–CO2–Na2CO3–MgCl2 system at 90, 120, and 150 ∘C and at 100 bar of CO2 pressure. The solution composition and solid phases were monitored with insitu Raman spectroscopy. At the conditions applied, we observed two mechanisms: direct precipitation of magnesite and simultaneous precipitation of magnesite and hydromagnesite followed by the transformation of the latter into the former. [Copyright &y& Elsevier]

Abstract: Carbon dioxide mineral sequestration is not as widely advocated as CO2 sequestration by other means such as underground storage alternatives, yet it possesses properties (capacity, permanency, energy economy) that can not be matched by other options. In this paper, our findings and results since GHGT-8 as well as current activities and near-future plans regarding CO2 mineral carbonation are presented. The focus lies on the use of fluidised bed (FB) reactors for the carbonation of magnesium silicates via magnesium oxide or magnesium hydroxide intermediates, at temperatures and pressures up to 600 ∘C, 100 bar (allowing for both sub- and supercritical conditions for CO2), supported by earlier experiments using pressurised thermogravimetric analysis (PTGA). In addition, as the production of reactive magnesium from silicate mineral is not straightforward, it receives special attention, and first results of magnesium hydroxide production from serpentine using different methods are presented. [Copyright &y& Elsevier]

Abstract: This paper evaluates the expected environmental impact of several promising schemes for ocean carbon sequestration by direct injection of CO2, and serves as a major update to the assessment by Auerbach et al. (1997) and Caulfield et al. (1997) of water quality impacts and the induced mortality to zooplankton. The impact assessment methodology from the earlier studies has been updated to incorporate the extended probit methodology of Sato et al. (2004), and revised mortality relationships based mainly on copepods were developed after a thorough review of publicly available CO2 toxicity data for zooplankton and fish. The impact assessment is conducted for three discharge approaches, each designed to maximize dilution over the water column: a point release of negatively buoyant CO2 hydrate particles from a moving ship; a stationary point release of CO2 hydrate particles forming a sinking plume; and a long, bottom-mounted diffuser discharging buoyant liquid CO2 droplets. Two of these scenarios take advantage of the enhanced dilution offered by CO2 hydrate particles, and are based on ongoing laboratory and field studies on the formation and behavior of such particles (Chow et al., 2008). Overall, results suggest that it is possible with present or near present technology to engineer discharge configurations that achieve sufficient dilution to largely avoid acute impacts. In particular, the moving ship hydrate discharge is identified as the most promising due to its operational flexibility. In addition to lethal effects, sub-lethal and ecosystem effects are discussed qualitatively, though not analyzed quantitatively. The main conclusion from our analysis is that ocean carbon sequestration by direct injection should not be dismissed as a climate change mitigation strategy on the basis of environmental impact alone. Rather, it can be considered as a viable option for further study, especially in regions where geologic sequestration proves impractical. [Copyright &y& Elsevier]

Abstract: This paper presents strategies for producing negatively buoyant CO2 hydrate composite particles for ocean carbon sequestration. Our study is based on recent field observations showing that a continuous-jet hydrate reactor located at an ocean depth of 1500 m produced curved negatively buoyant cylindrical particles with diameters ∼2.5 cm and lengths up to ∼1 m. Accordingly we performed new laboratory experiments to determine the drag coefficient of such particles and, based on the measured drag coefficient and the initial settling velocity observed in the field, have concluded that the reactor efficiency (percentage of liquid CO2 converted to hydrate) in the field was ∼16%. Using the dissolution rates observed in the field, we conclude that such particles would ultimately sink to depth below discharge of ∼115 m. We have also predicted the sinking depth of particles potentially produced from various scaled-up reactors and have shown that, for example, a 10 cm diameter particle produced with a hydrate conversion of 50% could reach the ocean bottom before completely dissolving. In a real sequestration scenario, we are interested in following large groups of hydrate particles released continuously. We have previously shown that increasing particle size and hydrate conversion efficiency enhances the sinking of hydrate particle plumes produced by the continuous release of CO2 in a quiescent ambient, but that a sufficiently strong current will cause the entrained particles to separate from the plume and settle discretely. In the latter case, particles of different sizes and hydrate conversions (hence different settling velocities) will follow different settling trajectories as they dissolve. This particle fractionation, if employed deliberately, spreads the discharged CO2 in the down current and vertical directions, enhancing mixing, while turbulent diffusion helps spread the CO2 in the third direction. A numerical model that incorporates these processes is used to predict the downstream concentrations and changes in pH from such particle plumes in a ‘strong’ current. An extension of this model simulates hydrate particles that are released continuously from a moving ship. Because of the ship speed, such particles would never form a coherent plume, but the combination of particle fractionation and advection due to the ship motion produces excellent dilution of the discharged CO2. [Copyright &y& Elsevier]

Abstract: The effectiveness of CCS, i.e. its emission abatement potential in relation to the possibility of leakage of CO2 from geological reservoirs once this greenhouse gas has been stored artificially underground, will be among the main determinants of whether CCS can significantly contribute to a deep cut in global CO2 emissions. This paper presents an analysis of the economic and climatic implications of the large-scale use of CCS for reaching a stringent climate change control target, when geological CO2 leakage is accounted for. The natural scientific uncertainties regarding the rates of possible leakage of CO2 from geological reservoirs are likely to remain large for a long time to come. We present a concise analytical inspection, as well as an analysis with a more detailed integrated assessment model, proffering insight into the economics of geological CO2 storage and leakage. CO2 leakage lowers the value of CCS as climate mitigation option below the prevailing level of the CO2 tax. We therefore employ a definition for the effectiveness of temporary carbon storage as the net present value of the total stream of avoided emissions. We calculate the effectiveness of CCS under two leakage models (an exponential model with a constant seepage rate and a two-layer model with a bell-shaped time-dependent seepage rate) and with different assumptions regarding (1) the carbon tax growth rate relative to the interest rate and (2) the average CO2 storage life-time. We introduce the expression for the effectiveness of CCS in a top-down integrated assessment model that represents three main CO2 emission reduction options: energy savings, a carbon to non-carbon (renewable) energy transition and the use of CCS. We find CCS to remain a valuable option even with CO2 leakage of a few %/yr, well above the maximum seepage rates that we think are likely from a geo-scientific point of view. [Copyright &y& Elsevier]

Abstract: CIS based polycrystalline semiconductors are used for thin film solar cells in laboratory and industry. Nevertheless, even for highly efficient absorbers from different growth techniques, these films are reported to contain inhomogeneities from nanometer to millimeter scale. In this paper we have analyzed inhomogeneities on a sub-μ m scale of CuIn(Se,S)2 solar cell absorber materials processed by annealing of elemental layer precursors using high spatial resolution cathodoluminescence mapping. The measurements were carried out in a scanning electron microscope which has cathodoluminescence (CL) and energy dispersive xray fluorescence (EDX) capabilities to study materials composition. Cathodoluminescence from CuIn(Se,S)2 at energies around 0.9 eV to 1.2 eV was detected by a spectrometer with a cooled InGaAs photo diode array. For better luminescence signals, the samples were cooled down to 80K (liquid nitrogen). From the energetic position of the cathodoluminescence peaks we have deduced the varying CuIn(Se,S)2 materials composition. EDX measurements were carried out to verify the CL. [ABSTRACT FROM AUTHOR]

Abstract: Double barrier Quantum Dot structures are potential candidates for Energy Selective Contacts for Hot Carrier Solar Cells. Silicon QD in SiO2 matrix is studied for its energy selectivity using a two dimensional model. The impact of the disorders- configurational, morphological, thickness variations of the SiO2 barriers- on conductance and selectivity of the structure is studied. Application of an external electric field modifies the confinement potential and thus the resonant properties of the structure. The impact of the applied electric field on the properties of the energy selective contact is also studied in this paper. [ABSTRACT FROM AUTHOR]

Abstract: Back diffusion of electrons in the p-i interface region in a-Si:H solar cells limits the open circuit voltage. Implementing a wide gap p-i interface layer is a well-known technique to enhance the open circuit voltage. The enhancement relies on the wide band gap, as well as on the band offset in the conduction band, which results in a barrier for back-diffusing electrons. In our research we focus on the exploration of wide band gap materials that optimize the band gap and the conduction band off set, while also having a low defect density. In this paper, we perform a comparative investigation of hydrogenated a-SiC:H and a-SiN:H on the basis of the optical band gap, the defect density and the performance of solar cells implementing the material at the p-i interface. We find that, although the a-SiC:H interface layer enhances the open circuit voltage with respect to a solar cell without interface layer, increasing the width of the band gap does not result in a further enhancement of the open circuit voltage. The performance of the solar cells implementing a-SiN:H at the p-i interface is low. This is attributed to the high defect density of the a-SiN:H. [ABSTRACT FROM AUTHOR]

Abstract: The present paper provides evidence that Fe can be incorporated into NiSi2 precipitates by solid-state diffusion. Furthermore, analysis of Si crystals contaminated with Ni and Fe at 1100 °C and post annealed at 600 °C and 800 °C for 20–240 min revealed a strong indication that this incorporation is limited by bulk diffusion rather than incorporation kinetics. [Copyright &y& Elsevier]

Abstract: In this paper we report a laboratory scale evaluation test of MEA degradation associated with analysis of degradation products and an evaluation of different oxidation inhibitors. Control of oxidation with inhibitors selected among conventional antioxidants was found to be unsuccessful. New classes of chemicals were investigated and MEA oxidative degradation was considerably reduced using specific inhibitors. The inhibition was found to be effective with 40% MEA and was successfully extended to others amines such as DEA, MDEA and AMP. [Copyright &y& Elsevier]

Abstract: This paper studies an ionic liquid (IL) 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl) imide ([EMIM][TFSI]) containing Zn2+ ions as a novel functional group for CO2 absorption. Their physical properties including the density, decomposition temperature, phase transition temperature, heat capacity and viscosity have been characterised. The CO2 solubility measurements have been carried out under constant pressures of 0.1, 0.3, 0.5, 0.7 and 1.0 bar at 40 °C. The result shows an appealing solubility of 8.2 wt% CO2 at 1.0 bar. The real-time absorption kinetics was studied using a comprehensive diffusion model for a reacting system. Based on this model, the corresponding diffusion coefficients and the reaction rate constant have been obtained. The diffusion and reaction behavior of CO2 in the physical/chemical absorption has also been discussed. [Copyright &y& Elsevier]

Abstract: Tens of millions of tons per year of CO2 are being captured from raw feed gas by natural gas plants using solvent-based technologies comprising a pair of absorber and regenerator, and this CO2 is then being released to the environment. As interest in reducing CO2 emissions from natural gas plants has increased in recent years, CO2 capture and storage (CCS) has gained in importance. However, if a natural gas plant is provided with a CCS system, additional energy is required to compress the captured CO2. Therefore, JGC Corporation and BASF SE have started joint development of a new solvent-based CO2 capture technology, called HiPACT (High Pressure Acid gas Capture Technology), which improves the energy efficiency of the CO2 capture and compression units in a natural gas plant. HiPACT solvent is robust against the high temperatures associated with solvent regeneration at high pressures. Therefore, the regeneration process used in HiPACT can be operated well above atmospheric pressure, which significantly reduces the energy consumption of the CO2 compression unit. Further, HiPACT solvent absorbs a larger amount of CO2 per volume unit than other solvents, thus resulting in lower energy consumption for pumping and regeneration of the solvent. When compared to conventional technology, it is estimated that HiPACT can yield cost reductions of more than 25 percent. A recent pilot test has validated the key features of the HiPACT solvent, its thermal stability and CO2 absorption performance, and it has been decided to carry out a large-scale demonstration test. This paper presents the results of a batch test and a pilot test, both of which validated the key features of HiPACT, and presents the results of a case study which shows HiPACT’s advantages over state-of-the-art technology currently used worldwide. [Copyright &y& Elsevier]

Abstract: Absorption characteristics of CO2 into aqueous ammonia are the key factors to achieve simultaneous removal of pollutants from coal-fired flue gas by ammonia scrubbing. An experimental study with asemi-continuous flow reactor was conducted to investigate the CO2 absorption characteristic of aqueous ammonia solutions. Pure CO2 was chosen in order to avoid the effect by the other gas components in this paper. The effect on solution CO2 loading and CO2 absorption capacity, which is caused by ammonia concentration, CO2 inlet velocity and temperature, has been given. Furthermore, the effect on absorption characteristic and slippery characteristics of ammonia caused by additives is also covered. The experiment results show that, with increase of ammonia concentration, the solution CO2 loading increases while the CO2 absorption capacity decreases. Both the above two parameters decrease with the increase of CO2 inlet velocity, but the total reaction rate acts reversely. When the temperature reaches 15 °C or 35 °C, the absorption characteristic can reach the extreme points. Adding AMP into ammonia can enhance the absorption of CO2, and control the slippery of ammonia in the absorption process. What’ s more, 3% is a better choice for addition concentration. [Copyright &y& Elsevier]

Abstract: Power generation is one of the biggest sources of man-made carbon dioxide (CO2) emissions, the main anthropologic greenhouse gas. As the combustion of fossil fuels generates CO2 emissions, new technologies are required to enable the power sector to continue to meet the global demand for electric power, while controlling the CO2 emissions that contribute to global warming. To achieve meaningful reductions, it will be necessary to develop technologies that can be applied to both greenfield projects and to the existing fleet through cost effective retrofits. Among those technologies under development, Post-Combustion Carbon Capture and Storage (CCS) using the Chilled Ammonia Process (CAP) technology is one of the more promising solutions. Testing and technology development for CAP has been completed at the We Energies Field Pilot and is underway at the E.ON Karlshamn and AEP Mountaineer facilities. This paper will report on the progress being made at those three facilities and describe how the data being generated is contributing to the commercial scale-up of the technology. The current status of these facilities is as follows: [•] The We Energies Field Pilot, designed to capture over 15,000 metric tonnes/year of CO2, commenced operations in June 2008 and was operated through October 2009. This first of a kind Proof of Concept unit demonstrated that CAP could be applied to coal fired applications. [•] The E.ON Karlshamn Field Pilot, designed to capture over 15,000 metric tonnes/year of CO2, was commissioned in April of 2009 and captures CO2 emissions from a boiler combusting a high sulfur fuel oil. [•] The Product Validation Facility (PVF) at American Electric Power (AEP)’s coal-fired Mountaineer Power Plant, inaugurated in September 2009, is designed to capture and store 100,000 metric tonnes/year of CO2. The Chilled Ammonia Product Validation Facility treats a flue gas slipstream taken from a location downstream of Mountaineer’s existing selective catalytic reduction (SCR), electrostatic precipitator (ESP), and wet flue gas desulfurization (WFGD) systems. Deployment of a CAP facility in this configuration represents a significant step in the technology scale-up process. This project scope includes CO2 capture, compression, and storage in two geologic reservoirs with injection wellheads located on the plant property. AEP worked with Battelle to develop the geologic storage system. This paper describes the Chilled Ammonia Process Development Program and provides an update on the CO2 capture pilot plants status including the AEP Mountaineer Product Validation Facility. [Copyright &y& Elsevier]

Abstract: Global climate warming caused by emission of greenhouse gas including CO2 is one of serious problems nowadays. In an effort to mitigate CO2 emissions, one of most effectively clean energy plan is to produce power from coal using the integrated gasification combined cycle (IGCC). However, the cost of existing CO2 capture technologies is still too high. Utilization of large-solubility and low-cost absorbent for CO2 capture in IGCC can effectively reduce the electricity price increase caused by addition of CO2 removal unit. As it needs to trap CO2 before combustion under high pressure in IGCC absorption is considered to be a better choice. HPP (Hot Potash Process) uses aqueous solution of potassium carbonate as the absorbent. Compared to physical solvent absorption method Rectisol and Selexol, HPP has relatively low investment and relatively high CO2 recovery. Even in comparison with other chemical absorbent amine method HPP still has advantages as good chemical stability and low vapor pressure. In this paper several activators piperidine, piperozine, pyrazine, morpholine, imidazole, N-hydroxyethyl piperozine, Naminoethyl piperozine, AMP was tested respectively at 70 °C. As a result, piperidine activation works best, followed by N-(2-hydroxyethyl)piperazine, N-(2-aminoethyl) piperazine, 2-amino-2-methyl-1 -propanol and piperazine, pyrazine and imidazole is at its worst. Among them, N-(2-hydroxyethyl)piperazine is less volatile, more stable and suitable as the activator. Absorbing capacity and absorbing rate of CO2 in carbonate aqueous solution with HPZ increases by 5% or more than those with PZ. An improved HPP process is presented adopting the new activator. In this process two de-absorption two columns is designed operating at different pressure. This makes it possible to reuse the heat of condensation during high pressure de-sorption in reboiler of low pressure de-sorption. By preliminary calculating the novel process can save energy consumption obviously. The steam consumption, cooling water consumption and power consumption declines by 43.30%, 31.81% and 10.57%, respectively. It is expected to develop a low-cost technology for capture CO2 from IGCC in the future. [Copyright &y& Elsevier]

Abstract: An advanced hydrogen production system with CO2 separation is introduced in this paper, which is based on HyPr-RING and enhanced by dual chemical looping. The first chemical looping is for CO2 separation using lithium ortho-silicate (Li4SiO4) as a solid CO2 sorbent which can absorb CO2 around 650 °C with an exothermic reaction and regenerate around 800 °C. Another chemical looping by red-ox reaction of a metal oxide is applied to oxygen carrier in the gasification reactor and heat source to regenerate the sorbent. Copper oxide (CuO) is one of the suitable materials for oxygen carrier because reduction of CuO by carbon is exothermic reaction which benefits energy balance, while reduction of nickel oxide or hematite by carbon is endothermic reaction. Dry mixtures of copper oxide and graphite in various ratio and sieve mesh size were dropped into the reactor preheated at various temperatures and each component of product gas was quantified by gas meter and GC/TCD. Hydrogen production from graphite was confirmed even at around temperature of CO2 absorption, but in any test conditions, a simple mixture of CuO and graphite mainly produced CO2 by complete oxidation. [Copyright &y& Elsevier]

Abstract: Chemical Looping combustion (CLC) is an oxy-combustion technology in which the oxygen required for combustion is supplied by metal oxides known as oxygen carriers (OC). The OC particles are employed to continuously transfer oxygen from an air reactor to a fuel reactor where oxygen is delivered to the fuel. This technology is regarded as one of the most promising CO2 capture technology in terms of efficiency penalty and cost reduction. Various CLC configurations have already been developed and tested in laboratory pilot plant scales. However more investigations are required to achieve optimized process operation. Among the different points to address, control of solid circulation rate between reactors is of highest importance regarding its effect on determination of oxygen transfer rate and solid oxidation state. A novel CLC configuration is proposed here where reactions are carried out in interconnected bubbling fluidized beds. Solid circulation rate control is achieved independent from gas flow rate in rectors through use of pneumatic non-mechanical valves as high temperature limits use of mechanical valves. Loop seals are also employed to minimize gas leakage problem. A 10 kW prototype CLC unit based on this configuration has been designed and built at IFP-Lyon in cooperation with TOTAL to operate with nickel-based oxygen-carrier particles. Successful operation has been obtained with CH4 as fuel resulting in more than 99% CH4 conversion to CO2. The effect of operating variables, reactor temperature and degree of reduction of particles on the gas conversion will be discussed in this paper. [Copyright &y& Elsevier]

Abstract: In-situ CO2 capture in coal utilization captures CO2 during coal combustion or gasification such as Oxygen fuel combustion or HyPr-RING. coal gasification processes. Regarding Oxufuel combustion, Callide Oxyfuel Project has been being conducted as the world first project to apply the technology to an existing power plant, Callide A Power Station #4 unit (30MWe) with injection of captured CO2 into the underground. This is a Japan-Australia collaboration project and JCOAL participates in it as a supporting collaborator. JCOAL also proposed a novel coal gasification method-,HyPr-RING (Hydrogen Production by Reaction-Integrated Novel Gasification). HyPr-RING method utilizes a chemical looping with the calcium cycle, in which CaO (or Ca(OH)2) captures CO2 during coal gasification completely to form CaCO3 and release heat for gasification to produce near pure hydrogen in one gasifier. This paper introduces the current developing status of the HyPr-RING method, mainly including the experimental examination of the transition of sorbent particle size distribution, ash and sulfur concentration of materials at several locations of gasification and calcination system for the HyPr-RING process. And the plant cold gas efficiency which should be affected by ash separation was also analyzed. As the results, it was found that coal ash and sulfur concentrated highly in the process of calcination after cyclone. If it is possible, separate and remove ash and sulfur by applying devices like filter or/and cyclone separator, the plant coal gas efficiency may raise 2 points than that in the previous study in which a part of recycled sorbent was rejected without separation. One method for reducing CO2, the green house gas emissions is to capture CO2 before it releases into the atmosphere and then sequestrate it. Active lime (main component, CaO) can be used to capture CO2 in the exhaust gas or in the reactor from fossil fuels utilization effectively. That is calcium oxide (CaO) absorbs CO2 to yield calcium carbonate (CaCO3) (Eq.(1)), then the CaCO3 is thermally decomposed to CaO again and release nearly pure CO2 (Eq. (2)) for sequestration. To obtain a nearly pure CO2 stream from CaCO3 decomposition, the heat for decomposing CaCO3 can be supplied by combusting fossil fuels, such as coal and natural gas, in a calciner with oxygen fuel combustion. The oxygen diluted by CO2 (CO2 cycle) or H2O (steam cycle), in order to obtain near pure CO2 stream from CaCO3 decomposition. In our previous studies4−6, it was clarified that calcinations of limestone (main component, CaCO3) in a fluidized bed calciner can be performed in CO2 cycle atmosphere when the bed temperature was raised above 1293 K, whereas with 60% steam cycle in atmosphere, limestone can be decomposed at comparatively lower temperature, such as 1173 K. The decomposition conversions of the limestone were about 95% and 98%, in CO2 cycle and in steam cycle atmospheres, respectively. Reducing the calcinations temperature of limestone was helpful to produce more than 30% active CaO as shown in previous study4−6. In this study, the energy of CaCO3 calcination process by H2O (steam) cycle was analyzed and compared with CaCO3 calcination process by CO2 cycle. For process calculations, the mass and energy flows were calculated iteratively, based on the input and output balances, until err [(input-output)/input] was <0.01. Analysis showed that, although H2O (steam) cycle calcination had calcination energy more about 3.6% than CO2 cycle due to water evaporation latent heat loss, however, the calcination energy per active CaO was lowest for H2O (steam) cycle. [Copyright &y& Elsevier]

Abstract: Chemical-looping combustion (CLC) is a combustion concept with inherent separation of CO2. The process uses a solid oxygen carrier, which consists of metal oxide, to transfer the oxygen from air to fuel. This paper presents findings from batch tests performed in a 10 kWth CLC pilot for solid fuels. The pilot, which is the world’s first chemical-looping combustor for solid fuels, is based on interconnected fluidized-bed technology and features a fuel reactor (FR) and an air reactor (AR) as the principal reaction chambers. In the FR, fuel is gasified with steam whereupon gasification products react with the oxygen carrier to form, ideally, CO2, H2O and SO2. Oxygen-carrier particles exit the FR through a weir and are led to the AR, where they are regenerated to their oxidized state. The pilot has been operated using a natural iron-titanium ore called ilmenite as oxygen carrier. Previous continuous tests have demonstrated a need for batch tests in order to obtain complementary information on system performance. In this study, five fuels were fed to the fuel reactor in batches of 20–25 g at four temperatures; 940 °C, 970 °C, 1000 °C and 1030 °C. By using devolatilized fuel, it was possible to determine (a) oxygen demand associated with syngas from char gasification as well as (b) kinetics of char conversion to gas. Rates of char conversion were found to be temperature dependent, as expected, whereas no temperature dependence was found for the oxygen demand. Activation energies for conversion of char to gas were calculated using Arrhenius plots. The minimum oxygen demand for char was found to be around 5%. [Copyright &y& Elsevier]

Abstract: The Calcium Looping (CaL) process using CaO as sorbent for capturing CO2 from flue gases is a promising postcombustion CO2-capture technology that is economically competitive with other capture technologies with an overall increased output in electric power and a low electric efficiency penalty associated with CO2 capture. The process can be realized in a Dual Fluidized Bed (DFB) system utilizing a Circulating Fluidized Bed (CFB) reactor as carbonator operating at 600–700 °C and a second CFB as regenerator operating at temperatures between 850–950 °C. The separation of CO2 from the flue gas takes place through the carbonation reaction (CaO+CO2→CaCO3). The regeneration of the sorbent is realized via the reverse reaction in the regenerator at higher temperatures. The feasibility of the CaL process has already been shown at IFK, University of Stuttgart on a lab-scale size. In order to investigate the calcium looping process using real combustion flue gas and to evaluate the process on a long-term basis, a 200 kWth pilot plant has been built at IFK. This paper delineates the design of the pilot plant to capture over 90% CO2 and provides an overview of the main components and the control philosophy. First results from the successful commissioning of the pilot plant are also shown. [Copyright &y& Elsevier]

Abstract: Within the frame of an EC financially supported project - LIFE05 ENV/IT/000874 GHERL (Greenhouse Effect Reduction from Landfill)–a pilot plant was set up in order to demonstrate the feasibility of applying chemical absorption to remove carbon dioxide from landfill gas. After proper upgrading - basically removal of carbon dioxide, hydrogen sulphide, ammonia and other trace gas compound–the gas might be fed into the distribution grid for natural gas or used as vehicle fuel, replacing a fossil fuel thus saving natural resources and carbon dioxide emissions. Several experiences in Europe have been carried out concerning the landfill gas - and biogas from anaerobic digestion - quality up-grading through CO2 removal, but in all of them carbon dioxide was vented to the atmosphere after separation, without any direct benefit in terms of greenhouse gases reduction. With respect to those previous experiences, in this work the attention was focused on CO2 removal from landfill gas with an effective capture process, capable of removing carbon dioxide from atmosphere, through a globally carbon negative process. In particular, processes capable of producing final solid products were investigated, with the aim of obtaining as output solid compounds which can be either used in the chemical industry or disposed off. The adopted absorption process is based on using aqueous solutions of potassium hydroxide, with the final aim of producing potassium carbonate. Potassium carbonate is a product which has several applications in the chemical industry if obtained with adequate quality. It can be sold as a pulverised solid, or in aqueous solution. Several tests were carried out at the pilot plant, which was located at a landfill site, in order to feed it with a fraction of the on-site collected landfill gas. The results of the experimental campaign are reported, explained and commented in the paper. Also a discussion on economic issues is presented. [Copyright &y& Elsevier]

Abstract: The first post-combustion capture pilot plant in Germany was constructed and commissioned in July 2009 at BoA 1 in Niederaussem, the most advanced and efficient lignite-fired power plant unit in the world, as part of the joint development programme of RWE Power, BASF and Linde that is aiming at a highly efficient CO2-scrubbing technology for power plants. The test programme at the pilot plant focuses not only on the energy demand for CO2 capture, solvent stability and corrosion resistance of innovative materials but also comprises an extensive analysis programme regarding emissions. Therefore, the pilot plant is in particular equipped with an online gas-analysis system to continuously measure the composition of the inlet and outlet gas streams. In addition, an extensive sampling and measurement programme is being carried out with the aim of making up the balance of trace elements in the gaseous flows including components that are normally not determined. For the liquid drain streams, a wide range of physical and chemical data is collected in parallel with the analysis of the gas streams. This paper summarises the results of the measurement programme and the operational experience regarding solvent losses for the benchmark solvent monoethanolamine (MEA). Some of the results are compared with the outcome of other test facilities by way of example. [Copyright &y& Elsevier]

Abstract: Climate change mitigation is a dynamic area that, as it is addressed, brings new challenges to other environmental aspects. Carbon capture and storage (CCS) plants are the latest development in a series of environmental controls and have some distinctive features that could potentially lead to other wider environmental problems. Whilst CCS represents a significant step towards cutting greenhouse gas emissions, consideration needs to be given to the potential wider environmental consequences especially in terms of pollutant emissions and local air quality impacts. Challenges remain for existing plants which will need to consider the most cost-effective strategies for installation of CCS plant balanced against managing air quality impacts as dispersion characteristics change. In the case of post-combustion carbon dioxide (CO2) capture technology, which is the focus of this paper, removal of CO2 from the main flue gas stream requires diversion of the flue gas through the CCS process, before it arrives at the exhaust stack. This flue gas stream may be all or part of the total plant flow or for multi-unit plants may be diverted from specific power generation units into the CCS plant before exhausting to atmosphere, either through returning back to the existing stack or through a new dedicated stack. This diversion and subsequent emission in itself poses an engineering challenge. In particular, the integration of the CCS process with the existing plant must also ensure that the diverted flue gas still achieves adequate dispersion as it contains residual levels of pollutants such as nitrogen oxides (NOx) and sulphur dioxide (SO2), despite the fact that the CCS process itself may reduce some of these pollutant levels further as a process by-product. Power plants which incorporate CCS will still be required to adhere to the appropriate pollutant emission limits and ensure effective dispersion to minimise the risk of breaching local air quality standards. This paper draws on experience gained through post-combustion CCS projects and addresses the potential effects of CCS on air quality, in the case of carbon capture retrofits. The findings of this paper are relevant to project developers, power generators and policymakers globally who have an interest in the potential for CCS to provide an emissions abatement option for existing thermal assets in the short and long term. [Copyright &y& Elsevier]

Abstract: Aqueous ammonia can be used to capture CO2 from flue gas of coal -fi red power plant with acceptable CO2 removal efficiency, high loading capacity of CO2, low corrosion, low cost, and less degradation, and it could remove other acid gas pollutants at the same time. However, the CO2 absorption rate and mass transfer in aqueous ammonia still need to study more deeply. The mass transfer characteristics of CO2 in aqueous ammonia were investigated in this paper. A small wetted wall column (WWC) was used to study the kinetics of CO2 absorbed in aqueous ammonia. The correlation of gas -side mass transfer coefficient kg was fitted as Sh=3.79(Re×Sc×d/h)0.486 based on the experimental data of CO2 absorption in 30%wt MEA solution for this WWC reactor. The reaction rates of CO2 in 1 wt%, 2.5 wt%, 5 wt% to 7.5 wt% aqueous ammonia were measured at the temperatures of 10 °C, 20 °C, 30 °Cto 40 °C, and the second-order reaction rate constant k2 was calculated. The termolecular mechanism model was used and discussed according to the experimental results. The kinetics constants of kT NH3 in termolecular mechanism were also fitted in this paper. [Copyright &y& Elsevier]T H2O in termolecular mechanism were also fitted in this paper. [Copyright &y& Elsevier]

Abstract: The most promising process for Post Combustion Carbon Capture (PCC) is reactive absorption. For the design and scale-up of this process, reliable process models are needed. To achieve this, the models need to not only reliably describe the physical and chemical equilibria in the reacting systems but also to account for both mass transfer and reaction kinetics. Consequently, the models are complex and contain a large number of input parameters for describing fluid dynamics and physico-chemical properties. In order to assess the required quality of the input, the sensitivity of the simulation results to the parameters has to be known. This paper presents results from such a sensitivity study for a typical operating point of a PCC pilot plant with 0.3 g/g monoethanolamine (MEA) in water as the solvent. A rate-based model and its input parameters are introduced and describe the pilot plant results well. The most relevant input parameters of the model are systematically varied and the influence of that variation on the simulation results is monitored. Absorber and desorber are considered separately. The results are sensitive to most of the studied parameters. High sensitivities are found for the interfacial area, the Henry’s law constant and the enthalpy of absorption as well as for the parameters describing the equilibrium and kinetics of the carbamate formation and the amine protonation equilibrium. [Copyright &y& Elsevier]

Abstract: We have examined the capture of carbon dioxide from flue gas by adsorption on solid sorbents using an equilibrium model for a packed bed temperature swing adsorption (TSA) process for a wide range of sorbents. This model determines the working capacity of the sorbent by looking at the difference between the equilibrium adsorbed concentrations at the adsorption and desorption conditions, and uses the sensible and latent heating requirements to determine the minimum energy usage. Using the results of this model, a class of sorbents can be constructed that have nearly identical physical properties but variable heats of adsorption for carbon dioxide to mimic different adsorption mechanisms. Parametric studies are run to determine the calculated minimum energy requirements per ton of carbon dioxide captured for this class of sorbents and a global minimum is found. This paper also discusses the effect of heat of adsorption on adsorption isotherms and what isotherm shapes are most beneficial for minimizing energy usage in carbon capture. [Copyright &y& Elsevier]

Abstract: Packed towers are common as gas/liquid contacting units for separation processes. Several studies have been performed to measure and model pressure drop, liquid hold-up and effective mass transfer area. However, most investigations have concentrated on distillation operation and the correlations obtained may not be directly applicable to reactive absorption. The present work presents a study of hydrodynamics and mass transfer properties of Sulzer structured packing Mellapak 2X using both an inorganic and an amine solvent. The pilot plant has an absorber column with packing height of 5 m and diameter 0.5 m. In this paper results for absorption studies and pressure drop, liquid hold-up and effective mass transfer area are presented. Dependencies of liquid flow, gas flow and viscosity were in agreement with correlations found in literature. New correlations for the hydrodynamic characteristics will be implemented in an in-house software as a basis for absorber and desorber design. [Copyright &y& Elsevier]

Abstract: This paper describes an investigation for multi-stage systems used in coal-fired power plant. The whole work was divided into two steps: energetic and economic analyses. In the first step: on the basis of a serial concept, through varying the position of compressors and vacuum pumps, recycling the retentate of the 2nd membrane to the feed side of the 1st membrane, a cascade variant was developed and analysed. In the second step: an economic model was developed to calculate the capture cost of the cascade system. The total cost is composed of investment cost, operation and maintenance (O&M) cost and electricity cost. A correlation between the membrane parameters: selectivity & permeability and capture performance: energy consumption & capture cost was built up. Using Polyactive® membrane developed by GKSS with CO2 permeance of 3 Nm3/m2hbar and CO2/N2 selectivity of 50, under the separation target of 70% degree of CO2 separation and 95 mol% CO2 purity, adopting the cascade membrane system in the 600 MW NRW-reference power plant, the specific energy consumption including CO2 compression (110 bar, 30 °C) is 256 kWh/tseparatedCO2 with 6.4%-pts efficiency loss. The capture cost is 31 euro/tseparatedCO2 , which could be a promising solution as a retrofit for the existing power plants. [Copyright &y& Elsevier]

Abstract: IGCC power plants seem to represent one of the most appealing options to produce electric energy from coal and low grade solid fuels with interesting plant efficiency and low environmental impact. As a matter of fact the majority of gasification-based power plants are equipped with oxygen-blown gasifiers which have two main advantages with respect to air-blown reactors: high values of cold gas efficiency and an N2 deprived syngas. The aim of this paper is to compare two different oxygen production technologies for oxidant supply to the gasification island. An IGCC power plant with pre-combustion CO2 capture has been modelled considering: (i) a cryogenic distillation ASU based on a pumped liquid oxygen cycle; (ii) an innovative OTM-based oxygen production technology integrated in the power island. An overall heat and material balance has been estimated to evaluate plant performances and compare the two options; our thermodynamic analysis shows a promising improvement of the overall plant performance for the OTM-based IGCC nonetheless several key issues deserve a more in depth analysis to asses the real potentialities of membrane-based oxygen production technology. [Copyright &y& Elsevier]

Abstract: In the current paper, CaCO3 precipitation process via CO2 absorption into aqueous solution of Ca(OH)2 was investigated in a stirred semi-batch reactor. Mathematical model describing the precipitation process was developed by considering the absorption and reaction kinetics as well as hydrodynamic conditions in the system. The model allows to simulate the concentration profiles of reactive species (CO2, Ca2+, OH−, CaCO3, HCO3 −, H+, CO32−) in the gas and liquid phase as well as to predict the rate of CaCO3 formation. The volumetric mass transfer coefficient, characterizing CO2 transfer performance from gas phase into Ca(OH)2 solution as well as rate constant of the CaCO3 precipitation reaction, were estimated based on the experimental data and the developed model. The CO2 mass transfer enhancement factor due to chemical reaction was also estimated. [Copyright &y& Elsevier]

Abstract: To make the deployment of carbon capture possible, it is highly needed to develop original solutions that induce low energy penalty and that are easy to operate. This paper aims at presenting the DMX™ process developed at IFP Energies nouvelles based on special solvents which are characterized by the formation of two immiscible phases for given temperature and CO2 loading conditions. The concept of demixtion is briefly described in terms of physico-chemical properties, its interest and all required steps for appropriate process development are discussed. The corresponding process is presented and a technico-economic analysis is given. It is shown than one can reach a reboiler duty as low as 2.1 GJ/t CO2 which is significantly lower than the 3.7 GJ/t CO2 of the 30wt.% MEA reference process. It is also discussed that the energy consumption at reboiler cannot be the only parameter to consider for comparison with other processes and some further information about the DMX™ process are given. Operational issues are particularly discussed. In that sense, the performances of the DMX-1TM solvent in terms of degradation and corrosion are shown. Similarly a particular focus is made on the liquid/liquid separation which is a key aspect of the DMX™ process. [Copyright &y& Elsevier]

Abstract: Concentrating solar thermal (CST) technology has been commercially proven in utility-scale power plants that have been in operation since the 1980’s. CST uses reflecting surfaces to focus solar energy onto collectors, generating extreme heat than can be used for a variety of purposes. The current focus of CST is large-scale electrical power generation. However, new applications, such as solar fuels, are quickly gaining momentum. One key shortcoming of CST technology is its sensitivity to disruptions in sunlight availability over time. CST systems require either thermal energy storage or backup systems to operate during heavy cloud periods or at night. On the other hand, fossil-based energy systems have high availability and reliability, but they generate substantial CO2 emissions compared to equivalent CST processes. A novel solution would combine the benefits of CST technology and of fossil-fueled energy systems. Such a solar-fossil hybrid system would guarantee energy availability in the absence of sunlight or stored solar energy. The addition of carbon capture to these systems could reduce their carbon intensity to almost zero. This paper introduces three important solar-fossil hybrid energy systems: (1) Integrated Solar Combined Cycle (ISCC), (2) Solar-assisted post-combustion capture (SAPCAP), and (3) Solar gasification with CO2 capture. These novel concepts have great potential to overcome the inherent limitations of their component technologies and to achieve superior greenhouse gas mitigation techno-economic performance in large-scale applications. The paper describes the features of the three solar-fossil hybrid systems described earlier, discusses its advantages and disadvantages, and provides examples of applications. The goal of this manuscript is to introduce experts in the CCS and CST fields to the opportunities of integration between these technologies and their potential benefits. [Copyright &y& Elsevier]

Abstract: In conventional power plants, the attention paid to air in-leakage is minor. This is due to the low impact of air in-leakages on the cost effectiveness of the plant. However, in oxyfuel power plants the minimization of air in-leakages into the process becomes a crucial issue to improve the efficiency of the process. For this reason, it is an aim of the operator of an oxyfuel plant to identify and localize such leakages as early as possible to initiate appropriate maintenance steps. In the present, paper a data-based method is described that can serve as a monitoring tool for the plant. In case of increasing air in-leakages an early identification and localization of the disturbance is possible. The investigations are based on an experiment conducted in Vattenfall’s Oxyfuel Pilot Plant in Schwarze Pumpe, Germany. During the test leakage air was dosed into the process at several locations that are characteristic for leakages. The process data gathered in this experiment were later-on analyzed in a principal component analysis (PCA). It was found that the monitoring of appropriate process variables in a PCA model provides a possibility for both to identify increasing leakages and to localize the region where the leakage occurs. [Copyright &y& Elsevier]

Abstract: The oxygen requirements for oxycoal combustion in a coal-fired power station are unusual in several respects. The amount of oxygen required is large, for instance a 500  MWe power plant will require around 10,000 tonnes per day of oxygen. The oxygen purity is low and the pressure required is essentially atmospheric pressure. There is no demand for any significant quantity of co-products, such as argon or nitrogen. The parasitic nature of the power means that high efficiency is important but the large scale means that capital cost should also be minimised. These factors open up new possibilities to optimise the process cycle and machinery configuration to minimise the power consumption of the air separation unit without compromising the requirement for low cost. This paper presents the results of a study to develop Air Products’ air separation unit (ASU) offerings for oxycoal CO2 capture projects. A scalable “reference plant” concept is described to match particular sizes of power generation equipment, taking into account factors such as safety, reliability, operating flexibility, efficiency, and of course low capital cost. We describe the selection of a process cycle to exploit the low purity requirements as well as the options for compression machinery and drivers as the scale of the plant increases and the sizes of referenced equipment limit the possibilities. We also explore integration with other elements of the oxycoal system, such as preheating condensate or heating and expanding pressurised nitrogen. Finally, the advantages and disadvantages of different execution strategies for air separation unit projects are discussed, as well as alternative commercial models for the supply of oxygen. [Copyright &y& Elsevier]

Abstract: Coal-fired power stations under oxyfuel combustion produce a raw CO2 product which contains impurities such as water, oxygen, nitrogen and argon from excess oxygen and air leakages. There are also acid gases present, such as SO3, SO2, HCl and NOX produced as by-products of combustion. These acidic impurities will need to be removed from the CO2 stream before it is introduced into the pipeline to prevent corrosion and comply with possible regulations. There may also be stringent requirements on purity, particularly for applications such as enhanced oil recovery. A novel compression method of producing NO x -free, SO2free CO2 was proposed in GHGT-8 where SO2 and NO x are removed as H2SO4 and HNO3respectively by compression and water contact of the flue gas. At GHGT-9, initial experimental results were presented using actual fluegas via a sidestream from Doosan Babcock’s 160 kW coal-fired oxyfuel rig, showing the feasibility of the process eliminating 99% SO x and 90% NO x compounds. In this paper, we report on the effects of pressure, temperature, residence time and presence of water in a laboratory scale apparatus using synthetic flue gas. [Copyright &y& Elsevier]

Abstract: Alstom is developing a portfolio of solutions to address CO2 emission reductions. Among them is CO2 Capture and Storage (CCS) for which Alstom is developing several CO2 capture systems based on post-combustion and oxycombustion processes. This paper will be oriented to utility and industrial companies that would like to be prepared to CCS challenges and understand the key features of the CO2 capture technologies, in this article focus will be on oxy-combustion. This paper is also oriented to “oxy-experts” community for an update coming from pilots operation. It will describe key features of the different pilot projects with Alstom’s involvement and will describe the work performed in there. The development of CO2 capture technologies are being pursued by European and US suppliers in collaboration with utility companies, academia, the US DOE, the European Union, and universities. The first part of this article will address the work of Alstom and corresponding results in three major oxy pilots: • Vattenfall Schwarze Pumpe Oxy-combustion pilot plant (30 MWth, coal)) and corresponding results (pilot is in operation since September 2008, a full PC oxy-combustion chain has been under evaluation there). • An oxy tangentially fired boiler development project (coal) with co-funding from the US DOE and other organizations, which includes pilot testing at the 15 MWth scale, conducted in Windsor CT (US). This pilot has started operation in September 2009. • The TOTAL Lacq Oxy-combustion pilot plant (30 MWth, natural gas) where Alstom did the retrofit of a conventional boiler for its conversion into oxy-combustion. Considerable knowledge has been gained with these pilots through different considerations, both on boiler components but also on the integrated oxy chain. All these positive outcomes confirm the expectations of the community in oxy-development and open the door to the next development step of ∼250 MWel large scale oxy-fired carbon capture and storage (CCS) demonstration plants. This paper provides an update about the CO2 capture pilot plant operation and also present the technical challenges expected to be demonstrated during large scale demonstration plants. [Copyright &y& Elsevier]

Abstract: Doosan Power Systems has adopted an evolutionary approach to the design and implementation of OxyCoal™ technology combining well proven and commercially available components with state-of-the-art advances in technology, and is leading a number of UK Government supported collaborative projects that are developing oxyfuel combustion technology. The “Demonstration of an Oxyfuel Combustion System” OxyCoal 2 project aimed to demonstrate an oxyfuel combustion system of a type and size (40MWt) applicable to new build and retrofit advanced supercritical oxyfuel plant. Following conversion to oxyfuel firing, the Clean Combustion Test Facility (CCTF) became the world’s largest demonstration facility of an oxyfuel combustion system, and since the official opening on 24th July 2009 a test programme has been successfully undertaken to demonstrate the full-scale Doosan Power Systems first generation 40MWt OxyCoal™ burner on air and oxyfuel firing, achieving safe and stable operation across a wide operational envelope and CO2 flue gas concentrations in excess of 75% v/v dry, and up to 85% v/v dry. The OxyCoal 2 project is discussed in the paper and results from testing the full-scale 40MWt OxyCoal™ burner firing bituminous coal in both air and oxyfuel firing operation are presented. [Copyright &y& Elsevier]

Abstract: Vattenfall has constructed a 30MWth oxyfuel pilot plant located in Schwarze Pumpe in Germany. The plant has been in operation since September 2008. Several test campaigns have been carried out, and in this paper some of the main results and conclusions are described together with some points related to operating experience. The results will serve as a basis for the design and operation of the 250MWe oxyfuel demonstration plant to be constructed by Vattenfall in Jänschwalde, Germany. [Copyright &y& Elsevier]

Abstract: This paper illustrates the application of dynamic simulation for the development of CO2 processing plants which are part of oxyfuel power plants. It is shown how dynamic simulation models are used to study transient processes such as load changes and disturbances, to evaluate and improve process design concepts, and to develop control and operational strategies. Furthermore, key success factors for dynamic simulation, such as appropriate model visualization and an early integration into the engineering workflow, are discussed. In order to study the behavior of the entire oxyfuel process, the application of model reduction methods is proposed. This facilitates the integration of dynamic simulation models that were initially implemented using different simulation tools, into a common simulation platform. [Copyright &y& Elsevier]

Abstract: Oxyfuel combustion CO2 capture technology presents an excellent opportunity for achieving near zero emissions from the coal-fired power plants. In the oxyfuel technology, the volume of flue gas is reduced by a factor of four to five (on a dry basis) due to elimination/reduction of nitrogen from combustion. This reduced volume of CO2-rich flue gas has to be compressed to 25 to 35 bar (a) for purification, thus further reducing the actual volume of flue gas by a factor of 25 to 35. If the equipment for removing trace impurities (SOx, NOx and Hg) is installed downstream of the flue gas compressor, the capital investment could be significantly reduced compared to that for the air-fired operation. Furthermore, by processing the entire volume of flue gas in the CO2 purification unit, it is possible to remove and concentrate the trace impurities in the solid and liquid waste streams and to produce a vent stream with near zero emissions and a high purity CO2 relatively free of trace impurities. Praxair is developing an oxy-combustion flue gas purification technology that will leverage these synergies. This technology will reduce emissions of CO2, SOx and Hg by >99% and NOx emissions by >95% compared to an air-fired pulverized coal power plant. The benefits of the technology include management of air ingress problems, capital and operating cost savings for SOx and NOx removal, reduction in CO2 capture cost and production of high purity CO2 stream for sequestration. These benefits will translate to lower cost of electricity for power plants with CO2 capture. This paper presents the experimental data for the SOx/NOx removal and high CO2 recovery processes and the results of the commercial viability assessment. [Copyright &y& Elsevier]