Publications Database - List of capture publications |
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Reduction in the cost of pre-combustion CO2 capture through advancements in sorption-enhanced water-gas-shiftAndrew Wright, Vince White, Jeffrey Hufton, Edward van Selow, Peter Hinderink Sorption-enhanced water-gas-shift (SEWGS) is a pre-combustion decarbonisation technology combining adsorption of CO2 with the water-gas-shift reaction. This process maximises the production of hydrogen from syngas whilst simultaneously capturing and separating CO2. Simulations have been completed to evaluate the use of SEWGS for power generation from natural gas with carbon capture. The modelling results show that using the SEWGS process could significantly reduce the cost of capturing CO2 versus a reference design that uses amine absorption. Work has also been completed to show that using a counter-current steam-rinse step may be an improvement over a co-current CO2-rinse cycle proposed previously. © 2008 Air Products and Chemicals, Inc. All rights reserved. Keywords: Sorption Enhanced Water Gas Shift; SEWGS; Hydrotalcite; Pressure Swing Adsorption. Source: Greenhouse Gas Control Technologies (GHGT) conference, 16-20 November 2008 |
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Redesign, Optimization, and Economic Evaluation of a Natural Gas Combined Cycle with the Best Integrated Technology CO2 CaptureCristina Botero, Matthias Finkenrath, Michael Bartlett, Robert Chu, Gerald Choi, Daniel Chinn The Best Integrated Technology (BIT) concept for post-combustion CO2 capture was evaluated for a 400 MW natural gas combined cycle power plant. The power plant was redesigned and optimized to include exhaust gas recirculation, an amine reboiler integrated into the heat recovery steam generator, and a low-cost amine unit capturing 90% of the CO2 through absorption into a 30-wt% monoethanolamine solution. A detailed performance evaluation of the CO2-lean power plant as well as a cost estimation of the power island and CO2 compression sections of the plant was carried out in order to evaluate the performance penalty of CO2 capture, the additional costs associated with this technology, and the advantages relative to state-of-the-art solutions retrofitting the power plant with a conventional CO2 capture unit. © 2008 Elsevier Ltd. All rights reserved. Keywords: Best Integrated Technology; post-combustion CO2 capture; natural gas combined cycle; exhaust gas recirculation. Source: Greenhouse Gas Control Technologies (GHGT) conference, 16-20 November 2008 |
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The CCP2 Capture Program - North-American NGO MeetingCO2 Capture Project Covers favoured capture technologies, targets, and projects including CACHET, HMR-BIT in CLIMIT and CLCGASPOWER, as well as evaluation of integrated post combustion technology and chemical looping combustion and membrane water gas shift. |
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The Capture Program for Phase II (2004 - 2008)CO2 Capture Project Overview of the capture program for Phase 2 presented at the CCP2 NGO Focus Group Meeting in North America, December 2006. |
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CCP2 Capture Program - Stakeholder Meeting, Rio de Janeiro, 2007CO2 Capture Project Overview of CO2 capture activities presented at the CCP2 Stakeholder Meeting in Rio de Janeiro, Brasil, February 2007. |
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CCP2 Capture Program - NGO Focus Group Meeting, Washington DC, 2005Kaufman Overview of CO2 Capture Project work program presented at the CCP2 NGO Focus Group Meeting in Washington DC November 2005. |
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Vol 1 Chapter 24: An evaluation of conversion of gas turbines to hydrogen fuelGregory P. Wotzak et al, GE Energy, USA Abstract: Gas turbines can play a key role in reducing CO2 generation from fossil fuels. GE heavy-duty gas turbines are already in service in the chemical process industry on gaseous fuels containing up to 95% hydrogen by volume. Gas turbines are operating in integrated gasification combined-cycle refinery applications with the generation of hydrogen as a feedstock for hydro cracking. However, these process applications usually include other fuel constituents, which prompted the need for a study of gas turbine response when coupled to specific processes that are applied to CO2 capture. Relative to improving the economics of CO2 capture, the feasibility of converting existing natural gas units is an approach that needs to be examined. This study evaluated the suitability for hydrogen fuel utilization with GE’s Frame 5002C and Frame 6001B gas turbines at the BP Prudhoe Bay facility. These types of machines are in wide use in industrial and chemical production applications. GE evaluated the appropriateness of seven candidate machines for utilizing high hydrogen fuels from three candidate pre-combustion de-carbonization processes. The detailed requirements definition calculations included all candidate fuels. The three fuel choices representative of the different hydrogen generation processes that use natural gas feedstock were screened for their combustion properties and related combustion experience. All fuels evaluated were found to exhibit sufficiently acceptable combustion properties that meet the detailed requirements. One fuel was jointly selected by GE and the BP CO2 Capture Project team for further detailed study, with consideration of possible pre-blending fuel with steam upstream of the gas turbines for additional NOx abatement. Comparative evaluations were also continued as well with the other fuel choices. Relative performance changes in terms of output, heat rates and emissions at three points on the operating curve (maximum, normal operating point and minimum load) were determined at full load, minimum turndown and an intermediate load. In addition, comparative performance runs were performed at full load for all three candidate fuels, with a target NOx level of 25 ppm. The suitability of these machines was determined from the feasibility and cost of modifications to the flange-to-flange machine, controls, and fuel system to be able to utilize high hydrogen fuel. This feasibility study for gas turbine retrofit requirements to burn high hydrogen de-carbonized fuel has determined that the conversion of any or all the Frame 5 and/or Frame 6 units at Prudhoe Bay is not only possible, but brings significant advantages in increased power and reduction in emissions. Carbon Dioxide Capture for Storage in Deep Geologic Formations – Results from the CO2 Capture Project Capture and Separation of Carbon Dioxide from Combustion Sources - Volume 1 |
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Vol 1 Chapter 18: Design, scale up and cost assessment of a membrane shift reactorTed R. Ohrn et al SOFCo-EFS Alliance, USA Abstract: The objective of the design, scale up and cost assessment of membrane shift reactor project was to produce a detailed design and cost estimate of a commercial scale membrane water gas shift (MWGS) reactor. The requirements for the reactor were:
The flux of hydrogen through the membrane was approximately 234 MMSCFD. Two feasible MWGS reactor designs have been developed, which use either a planar or a tubular hydrogen separation membrane. The planar membrane is composed of a curved membrane supported by a corrugated Type 430 stainless steel sheet. Finite element analysis which considered the pressure, gravity, and differential thermal expansion loadings indicates that it is structurally adequate for 41.1 bar (600 psid) pressure loading at 450°C (842°F). A second MWGS reactor concept is based on a tubular membrane sized appropriately to contain the high pressure inside the tubes. An analysis tool to permit examination of different arrangements for the MWGS reactor was developed and bench-marked against the model developed in Phase I. This analysis tool determined the membrane area required for each reactor concept. The planar membrane reactor has the following characteristics:
The tubular membrane reactor concept has the high-pressure feed gas inside the tubes and the sweep gas flowing across the tube bank. The tube length was varied to meet the feed-side pressure drop constraint for a given tube diameter, and the tube pitch and baffle arrangement were varied to meet the sweep-side pressure drop constraint. The characteristics of the tubular reactor include:
The baseline planar design places the membrane internals inside of a conventional pressure vessel. The tubular membrane reactor concept, which was not designed as rigorously as the planar options, was based on standard shell and tube construction. The vessels are designed according to Section VIII, Division 1 of the ASME Boiler and Pressure Vessel Code, for an internal pressure of 41.4 bar (600 psig) at a vessel metal temperature of 454°C (850°F). The estimated order-of-magnitude cost to fabricate the baseline planar reactor is approximately $19 million. The estimate is based on input from various suppliers of materials and services, as well as manufacturers specializing in the fabrication of components specified for the reactor. In many cases, where detailed information is not yet developed, rough cost estimates were provided by vendors based on similar work and standard cost models. The alternative tubular concept was estimated at approximately $12 million. Carbon Dioxide Capture for Storage in Deep Geologic Formations – Results from the CO2 Capture Project Capture and Separation of Carbon Dioxide from Combustion Sources - Volume 1 |
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Vol 1 Chapter 17: Silica membranes for hydrogen fuel production by membrane water gas shift reaction and development of a mathematical model for a membrane shift reactorPaul P.A.C. Pex and Yvonne C. van Delft, Molecular Separation Technology, Energy Research Centre of the Netherlands, The Netherlands Abstract: One of the technologies for pre-combustion decarbonisation is the production of hydrogen rich fuel gas from fossil fuel feed stock by means of a water gas shift membrane reactor system. A study to develop and test hydrogen selective membranes for use in a water gas shift membrane reactor operating with sour synthesis gas has been sponsored by the CO2 Capture Project. The aim of the project was to demonstrate a proof of concept water gas shift membrane reactor for this purpose. As one of the potential membrane options in such a membrane reactor tubular microporous silica membranes have been made for testing with a simulated water gas shift mixture. With standard silica membranes the flux criteria can be met when no water is present in the feed. However, with water in the feed the flux drops to a value, which is a factor 3 below the target. At the start of the project it was clear that the permselectivity criterion of 100 was too high for microporous membranes, because a maximum H2/CO2 permselectivity of 39 was thus far measured for standard silica membranes. Selectivity improvement was focused on higher sintering temperatures, but increase of the H2/CO2 selectivity has not been experimentally proven. It was shown that H2S has no detrimental effect on a standard silica membrane and the H2/H2S selectivity is very high. Under the process conditions, so including a relative high water concentration, the stability of the silica membrane is limited to days as expected. The hydrothermal stability has been improved by incorporating alkyl-groups in the silica structure (ECN patent pending). The modified silica membrane is stable for more than 1000 h under simulated steam atmosphere testing. A software model of the water gas shift membrane reactor has been developed. The model simulates a counter current water gas shift membrane reactor with microporous membranes (silica and zeolite) and dense (palladium and proton conducting) membranes and copes with the isothermal and non-isothermal operation of the membrane reactor. The model is implemented as an Aspen Plus User Model (Aspen Plus, version 11.1) and is written in FORTRAN. Carbon Dioxide Capture for Storage in Deep Geologic Formations – Results from the CO2 Capture Project Capture and Separation of Carbon Dioxide from Combustion Sources - Volume 1 |
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Vol 1 Chapter 16: Hydrogen transport membrane technology for simultaneous carbon dioxide capture and hydrogen separation in a membrane shift reactorMichael V. Mundschau et al, Eltron Research Inc, USA Abstract: A wide variety of dense hydrogen transport membranes were tested for feasibility of resisting a minimum differential pressure of 3.10 MPa while extracting hydrogen from simulated high pressure water gas shift reactors operating at 693–713 K at an absolute pressure of 3.20 MPa and containing a hydrogen partial pressure of 1.31 MPa. Membranes were tested for compatibility with operating conditions of commercial water gas shift catalysts of 90 wt% Fe3O4/10 wt% Cr2O3. Best hydrogen flux results were achieved using select metal membranes of Group IVB and VB elements (i.e. Nb, Ta, V, Zr) and their alloys coated with submicron thick layers of palladium. Free standing, unsupported disks, 1.6 mm in diameter, of select metals and alloys were found to resist the target differential pressure of 3.10 MPa with the target partial pressure of hydrogen of 1.31 MPa while producing a hydrogen flux of 2.1 mol m-2 s-1 at 713 K at essentially 100% selectivity. At a 3.10 MPa differential pressure and a hydrogen partial pressure of 2.90 MPa, a record hydrogen flux of 2.5 mol m-2 s-1 was achieved at 713 K. It was concluded that the metal membranes appear superior to other classes of membrane tested for separation of H2 from CO2 at high pressure and are the most likely to be cost effective in scaled up reactors. Because commercial water gas shift catalysts are likely to be deactivated by sintering when used above about 713 K, proton conducting ceramic membranes, which typically require temperatures well above about 1000 K, were eliminated from consideration. Thin films of palladium supported on various porous materials were evaluated. In order to minimize interfacial stress between palladium and its potential substrates, which can lead to the formation of dislocations and cracks, a computer search of approximately 50,000 compounds was performed to select materials which would crystallographically match the cubic symmetry of the palladium crystal lattice and which would match the crystallographic lattice constants at the atomic level within about 2%. It was also desired to match coefficients of thermal expansion from room temperature to a maximum anticipated operating temperature of 713 K. From a dozen porous compounds tested, LaFe0.90Cr0.10O3-x and LaFeO3-x, performed best. However, it was concluded that, in general, hydrogen flux would likely be severely limited by gas phase diffusion of non-hydrogen gases through all conceivable thick porous supports needed to resist the extreme differential pressures, and that the predicted advantages of using micron-thin layers of palladium would be difficult to achieve. Also considered were dense cermets (ceramic metals) fabricated by sintering together powders of palladium or Group IVB–VB metals with ceramics which were lattice matched and matched for coefficients of thermal expansion. In the cermets tested, the hydrogen flux was predominantly through the metal phase (or along the metal ceramic phase boundaries) rather than through the ceramic phase. It was concluded that cost of scaled-up cermets of palladium might be prohibitive. Carbon Dioxide Capture for Storage in Deep Geologic Formations – Results from the CO2 Capture Project Capture and Separation of Carbon Dioxide from Combustion Sources - Volume 1 |
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