Publications Database - List of capture publications |
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Effect of Gas Impurities on the Behavior of Ni-based Oxygen Carriers on Chemical-Looping CombustionJuan Adánez, Francisco García-Labiano, Pilar Gayán, Luis F. de Diego, Alberto Abad, Cristina Dueso, Carmen R. Forero Chemical Looping Combustion (CLC) is a two-step gas combustion process that produces a pure CO2 stream, ready for compression and sequestration. A solid oxygen carrier (OC) circulates between two reactors and transports oxygen from the combustion air to the fuel. Since the fuel is not mixed with air, the subsequent CO2 separation process is not necessary. A key aspect in CLC process using refinery and industrial gases is to know the behavior of the oxygen carriers under real gas mixtures that contain impurities as for example, sulfur and light hydrocarbons. The objective of this work was to analyze the effect of these impurities on the behavior of a Nickel-based oxygen carrier prepared by dry impregnation on α-Al2O3. The tests were carried out in a continuous 500 Wth CLC plant. Based on these results, important conclusions with respect to design of CLC plants are derived, which can help to the development of this technology in the near future. © 2008 Elsevier Ltd. All rights reserved. Keywords: Chemical-Looping Combustion; nickel; oxygen carrier; sulfur; hydrocarbons; refinery gas. Source: Greenhouse Gas Control Technologies (GHGT) conference, 16-20 November 2008 |
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Natural minerals as oxygen carriers for chemical looping combustion in a dual circulating fluidized bed systemTobias Pröll, Karl Mayer, Johannes Bolhàr-Nordenkampf, Philipp Kolbitsch,Tobias Mattisson, Anders Lyngfelt, Hermann Hofbauer A first experimental campaign has been conducted at a 120 kW fuel power dual circulating fluidized bed installation for chemical looping combustion of gaseous fuels. In these test runs natural ilmenite (FeTiO3) has been used as oxygen carrier material. The plant consists of two interconnected circulating fluidized bed reactors (stainless steel construction, inner diameter: 0.15 m, height: air reactor 4.1 m, fuel reactor 3 m). Variations of fuel composition (natural gas, synthetic gas mixtures of H2 and CO), load, temperature and solids circulation rate have been performed for the bulk bed material. Further, natural olivine, (Fe,Mg)2SiO4, has been studied as an additive to increase hydrocarbon conversion. Despite the limited height of the risers, the results show reasonable fuel conversion for CO and H2 at 950°C. The conversion of natural gas, i.e. CH4, on the other hand, is relatively low for the pure ilmenite material at about 30-40%. A certain dependency of fuel conversion on load is found especially for CH4. Addition of natural olivine results in a moderate increase of CH4 conversion. © 2008 Elsevier Ltd. All rights reserved. Keywords: Carbon capture, Unmixed combustion, Chemical looping, Oxygen carriers, Ilmenite, Olivine, Dual fluidized bed. Source: Greenhouse Gas Control Technologies (GHGT) conference, 16-20 November 2008 |
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On the Performance and Operability of GE’s Dry Low NOx Combustors utilizing Exhaust Gas Recirculation for Post-Combustion Carbon CaptureAndrei T. Evulet, Ahmed M. ELKady, Anthony R. Brand, and Daniel Chinn The capture and sequestration of CO2 will be necessary to mitigate CO2 emissions from fossil fuel (coal, oil, natural gas or biomass) power generation facilities in a carbon constrained world. Post combustion carbon capture is a viable technology alternative to reduce CO2 emissions from power plants in the short term. The CO2 concentration in the exhaust gases of natural fired power plants can be increased through exhaust gas recirculation (EGR). A joint CO2 Capture Project (CCP) and GE study of the Best Integrated Technology (BIT) shows that EGR enables reduced exhaust gas flow to the post combustion capture plant and cost of the CO2 capture. This paper describes the experimental work performed at General Electric Global Research Center in order to better understand the risks of utilizing EGR in combination with dry low NOx (DLN) combustors. A research combustor was developed for exploring the dry low emissions capability of nozzles to operate in low O2 environment. A series of experiments have been conducted at representative gas turbine pressures and temperatures, in an EGR test rig. Exhaust gas generated in a first stage, at pressure, is used to vitiate the fresh air to levels determined by cycle models. Experimental results include the effect of applying EGR on operability, efficiency and emissions performance under conditions of up to 30% EGR (low oxygen). Our findings confirm the feasibility of EGR for enhanced CO2 capture, exceeding the expectations of operability and combustion efficiency predicted by models. In addition, we confirm benefits of NOx reduction while complying with CO emissions in Dry Low NOx Emissions combustors under low oxygen content oxidizer. © 2008 Elsevier B.V. All rights reserved. Keywords: Exhaust Gas Recirculation (EGR); Dry Low NOx(DLN); CO2; gas turbine; combustion; Best Integrated Technology (BIT); CO2 Capture Project. Source: Greenhouse Gas Control Technologies (GHGT) conference, 16-20 November 2008 |
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Hydrogen membrane reactors for CO2 captureD. Jansen, J.W. Dijkstra, R.W. van den Brink, T.A. Peters, M. Stange, R. Bredesen, A. Goldbach, H.Y. Xuc, A. Gottschalk, A. Doukelise In the European FP6 research project CACHET hydrogen palladium-based membrane reactors for pre-combustion CO2 capture from natural gas combined cycles are being developed. In the project both the electroless plating method used by DICP and the SINTEF two-stage membrane preparation method based on magnetron sputtering have been successfully up-scaled to membranes with a length of 50 cm. The membranes have been tested extensively with hydrogen/nitrogen gas mixtures, and with simulated feed gas for reforming and water gas shift conditions. The membrane performances in terms of flux, stability and separation efficiency were sufficient to start the design and construction of a membrane reactor test facility, the Process Development Unit (PDU), where membrane tests under relevant process conditions will be performed. Finally, process synthesis and techno-economic analysis indicate overall LHV efficiencies between 46.7 and 47.4 % LHV for natural gas combined cycle power plant with hydrogen membrane reactors for CO2 capture. The cost of electricity is estimated to 73 - 92 €/MWh. These figures are based on 2008 cost data, and the membrane performance after two years of membrane development in CACHET. © 2008 Elsevier B.V. All rights reserved. Keywords: Membrane reactors, CO2 Capture, Natural gas combine cycle, Costs. Source: Greenhouse Gas Control Technologies (GHGT) conference, 16-20 November 2008 |
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A technical and economical evaluation of CO2 capture from FCC unitsLeonardo F. de Mello, Ricardo D.M. Pimenta, Gustavo T. Moure, Oscar R.C. Pravia, Loren Gearhart, Paul B. Milios, Torgeir Melien The present work was focused on a technical and economical evaluation of two distinct CO2 capture technologies applied to an FCC unit, namely amine absorption and oxyfired FCC. All capital costs, utility requirements and chemical consumption of each technology were determined in order to allow the calculation of CO2 capture and avoided costs. The results showed a 45% decrease in CO2 capture cost for oxyfiring technology compared to the amine absorption alternative. As for the technical feasibility of oxyfiring in the FCC regenerator, a series of bench and pilot plant scale tests were performed. Product profile, stability of operation and the effectiveness of coke burn were evaluated. No significant changes from normal operation were observed. © 2008 Elsevier Ltd. All rights reserved. Keywords:FCC; CO2 capture; Oxyfiring; Oxycombustion. Source: Greenhouse Gas Control Technologies (GHGT) conference, 16-20 November 2008 |
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Performance of sorption-enhanced water-gas shift as a pre-combustion CO2 capture technologyE.R. van Selow, P.D. Cobden, R.W. van den Brink, J.R. Hufton, A. Wright The sorption-enhanced water-gas shift (SEWGS) process is a promising technology for pre-combustion decarbonisation. It is well suited for decarbonising syngas produced from natural-gas and coal based fuels in combined-cycle power production schemes. Higher capture rates could be obtained by SEWGS at lower efficiency penalties and at lower costs than by absorption. In the SEWGS process, multiple reactor vessels are packed with mixtures of CO2 sorption pellets and water-gas shift catalyst pellets. The technology is developed using potassium promoted hydrotalcite-based materials as the CO2 sorbent. In a first series of experiments, the performance of this material is investigated under typical SEWGS process conditions. The sorbent was loaded in 2 m and 6 m tall fixed-bed reactor vessels. Breakthrough capacities of 1.3 – 1.4 mmol/g are reported. After breakthrough the sorbent continues to take up CO2, albeit at a much lower rate. Total sorption capacities exceeding 8 mmol/g are observed. This capacity is attributed to the formation of MgCO3 in the bulk of the sorbent material and requires moderate to high partial pressures of CO2 and steam. The stability of the sorbent material during cyclic operation was demonstrated for more than 4,000 adsorption and desorption cycles. A stable and low slip of CO2 was established, corresponding to a carbon capture ratio of well above 90%. After investigation of the relevant sorbent characteristics, the reactor was loaded with sorbent and catalyst material in order to provide a proof-of-principle of the SEWGS technology and establish the performance and stability of sorbent and catalyst material. When the reactor was fed with a gas mixture that simulated a syngas typically produced by auto-thermal reforming of natural gas, it was demonstrated that carbon monoxide conversion can be enhanced from 55% in absence of a sorbent to 100% in the presence of a sorbent. Neither the change of gas composition nor the mixing of sorbent with catalyst did significantly impact CO2 breakthrough capacity. In a cyclic duration test, the carbon capture rate and carbon monoxide conversion were confirmed to be above 98% without excessive steam demand, and reasonably stable for at least 500 cycles. The experimental data will be used for modelling, cycle optimization, and scale-up to a pilot unit. © 2008 Elsevier Ltd. All rights reserved. Keywords: sorption-enhanced, hydrotalcites, water-gas shift reaction, pressure swing adsorption, pre-combustion capture, decarbonization, power plants, hydrogen production. Source: Greenhouse Gas Control Technologies (GHGT) conference, 16-20 November 2008 |
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Chemical-looping Combustion CO2 Ready Gas PowerTobias Mattisson, Juan Adanez, Tobias Proell, Rein Kuusik, Corinne Beal, Jan Assink, Frans Snijkers, Anders Lyngfelt This paper presents results from a 30-month project devoted to taking the chemical-looping combustion (CLC) technology to the next level of development. The project is part of the EU’s Sixth Framework programme with support from the CCP (Carbon Capture Project) and has mainly focused on the critical issues for an up-scaling of the technology. In an earlier project the CLC technology was demonstrated successfully for the first time for 100 h using Ni-based oxygen carrier particles using natural gas as fuel. The current project has built on these experiences and: i) established industrial-scale NiO particle production with suitable commercial raw materials. Oxygen carrier particles have been produced with both spray-drying and impregnation and investigated extensively with respect to parameters important for CLC operation, such as reactivity in batch and continuous operation, strength, defluidization phenomena, operation at high temperatures and effect of impurities such as H2S in the fuel; ii) extended operational experience in long term tests of particles in the available 10 kW prototype for more than 1000 hours combustion and iii) succesfully scaled-up and operated the process in a 120 kWth combustor using syngas and natural gas. Further, the project has included extended and verified modelling of the reactor system for scale-up in addition to process and technology scale-up and economic assessment. The paper will present the main results of the project. © 2008 Elsevier Ltd. All rights reserved. Keywords: Chemical-looping combustion; commerical oxygen carriers; scale-up; impuritites; integrity testing. Source: Greenhouse Gas Control Technologies (GHGT) conference, 16-20 November 2008 |
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CO2 Capture and Development of an Advanced Pilot-Scale Cryogenic Separation and Compression UnitKourosh E. Zanganeh, Ahmed Shafeen, Carlos Salvador At present, the use of fossil fuels in the current energy mix represents the largest source of CO2 emissions, and important greenhouse gas, which is largely blamed for global warming. It is estimated that roughly 26 to 30 percent of all CO2 emissions due to human activities come from fossil fuels used for generating electricity. Moreover, a variety of other industrial processes such as oil refineries, fertiliser and cement plants also emit large amounts of CO2. The oppurtunity therefore exists for a significant reduction of CO2 from industrial processes and power plants through CO2 Capture and Storage (CCS). Currently, there are three main pathways to capturing CO2 from fossil fuel energy conversion processes, namely, pre-combustion capture, post-combustion capture, and oxy-fuel combustion with CO2 capture. Among these approaches, pre-combustion and oxy-fuel combustion take advantage of the fact that CO2 capture is further facilitated by increasing the concentration of CO2 in the flue gas stream, or by increasing the flue gas pressure, or both. There are several different processes available for CO2 capture and compression from low-pressure flue gas streams rich in CO2. These processes vary from simple straight or once through low-temperature separation and compression to more comples processes involving some form of recycle and/or auto-refrigeration. Given the economic constraints often placed on the cost of CO2 capture, and based on energy demand of each process, the ultimate success of these processes hinges on further refining the existing ones or developing new processes that can lower the cost of CO2 capture. The CANMET Energy Technology Centre in Ottawa is currently pursuing a leading research and development programme in the field of near-zero emission fossil fuel technologies. This programme includes the development of next generation oxy-fuel combustion technologies, as well as the design and development of efficient CO2 capture and compression processes to recover CO2 from oxy-fuel and other fossil fuel energy conversion systems. In this paper, we present and discuss the technical challenges, development stages and commissioning of the CANMET's pilot-scale CO2 capture and compression unit (CO2CCU). This pilot-scale CO2 separation and compression unit provides an excellent test platform to study the impact of flue gas impurities on the CO2 capture process. This advanced gas separation system is first-of-a-kind pilot-scale unit that represents and integrated approach to oxy-fuel combustion of coal and other fossil fuels with CO2 capture for storage. © 2008 Elsevier Ltd. All rights reserved Keywords: Greenhouse Gas Emission, CO2 Capture, Low-temperature Gas Separation, CO2CCU. Source: Greenhouse Gas Control Technologies (GHGT) conference, 16-20 November 2008 |
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Performance of a NiO-based oxygen carrier for chemical looping combustion and reforming in a 120kW unitJohannes Bolhàr-Nordenkampf, Tobias Pröll, Philipp Kolbitsch, Hermann Hofbauer In this study the performance of two different Ni-based oxygen carriers in a 120kW chemical looping pilot rig at Vienna University of Technology is presented. A dual circulating fluidized bed (DCFB) system has been designed with the important characteristics of high solid circulation, very low residence times and a high power to solid inventory ratio. For all presented results the pilot rig is fueled with methane at 140kW fuel power. For both oxygen carriers high CH4 conversion and CO2 yield is achieved. Air to fuel ratio and temperature are varied. CH4 conversion at higher air to fuel ratio as well as at higher temperature seems to decrease. This phenomenon is linked to the Ni/NiO ratio of the particle which determines the catalytic activity and thus influences the CH4 conversion and the CO2 yield.
© 2008 Elsevier Ltd. All rights reserved. Keywords: Chemical Looping; Oxygen Carrier; Gas-Solid Reactor; Fluidized Bed System; Nickel Oxide. Source: Greenhouse Gas Control Technologies (GHGT) conference, 16-20 November 2008 |
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Recent development in the HMR pre-combustion gas power cycleJens B. Smith, Knut I. Aasen, Kjersti Wilhelmsen, Daniel Käck, Turid Risdal, Anita Berglund, Annette Stenersen Østby, Michael Budd, Tor Bruun, Bjørnar Werswick The focus area of the current HMR phase has been HMR process engineering and fabrication and testing of a small-scale monolith module. A new, less complicated HMR gas power cycle has been developed and benchmarked. The efficiency loss and CO2 capture are typically 8 %-point and 85 %, respectively, but more than 90 % of the installed membrane area of the original concepts is rendered superfluous. Small-scale monolith modules have been fabricated and tested under real HMR process conditions, demonstrating promising hydrogen flux and steam reforming according to equilibrium. © 2008 Elsevier Ltd. All rights reserved. Keywords: HMR; pre-combustion gas power cycle; CCS; hydrogen membrane; steam reforming catalysis. Source: Greenhouse Gas Control Technologies (GHGT) conference, 16-20 November 2008 |
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