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Waheed, Qari Muhammad Khalid. "Ultra-high temperature steam gasification of biomass." Thesis, University of Leeds, 2013. http://etheses.whiterose.ac.uk/5852/.
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In this research, hydrogen production from conventional slow pyrolysis, flash pyrolysis, steam gasification and catalytic steam gasification of various biomass samples including rice husk, wood pellets, wheat straw and sugarcane bagasse was investigated at ultra-high temperature (~1000 °C). During flash pyrolysis of the waste wood, the gas yield was improved to ~78 wt.% as compared to ~25 wt.% obtained during slow pyrolysis. The addition of steam enhanced the hydrogen concentration from 26.91 vol.% for pyrolysis to 44.13 vol.% for steam gasification. The comparison of pyrolysis, steam gasification and catalytic steam gasification in a down-draft gasification reactor at 950 °C using rice husk, bagasse and wheat straw showed a significant increase in gas yield as well as hydrogen yield. The hydrogen yield was enhanced from ~2 mmoles g-1 for pyrolysis to ~25 mmoles g-1 during steam gasification using a 10 wt.% Ni-dolomite catalyst. The higher hydrogen yield was due to the enhanced steam reforming of hydrocarbons and thermal cracking of tar compounds at higher temperature. When compared with the other catalysts such as 10 wt.% Ni-dolomite, 10 wt.% Ni-MgO, and 10 wt.% Ni-SiO2, the 10 wt.% Ni-Al2O3 catalyst showed the highest hydrogen yield of 29.62 mmoles g-1. The investigation on gasification temperature showed that the hydrogen yield was significantly improved from 21.17 mmoles g-1 at 800 °C to 35.65 mmoles g-1 at 1050 °C. The hydrogen concentration in the product gas mixture was increased from 50.32 vol.% at 800 °C to 67.41 vol.% at 1050 °C. The increase in steam injection rate from 6 to 35 ml hr-1 enhanced the hydrogen yield from 29.93 mmoles g-1 to 44.47 mmoles g-1. The hydrogen concentration increased from 60.73 to 72.92 vol.%. The increase was mainly due to the shift in the equilibrium of the water gas shift reaction as H2:CO ratio increased from 2.97 to 7.78. The other process variables such as catalyst to sample ratio, carrier gas flow rate showed little or no influence on the gas yield and hydrogen yield. The steam gasification of residual biomass char was performed at 950 °C to recover extra hydrogen. The presence of 10 wt.% Ni-Al2O3 in the gasifier improved the hydrogen yield to ~47 mmoles per gram of biomass as compared to the other catalysts such as 10 wt.% Ni-dolomite and 10 wt.% Ni-MgO. The gasification temperature showed a positive influence on hydrogen yield from 750 °C to 950 °C. The increase in steam injection rate from 6 ml hr-1 to 15 ml hr-1 enhanced the hydrogen yield from 46.81 to 52.10 mmoles g-1 of biomass.
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Yunt, Mehmet 1975. "Steam temperature regulation in fossil power plants." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/89876.
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Arnold, Ramsey Paul. "Silicon carbide oxidation in high temperature steam." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/76940.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 119-123).
The commercial nuclear power industry is continually looking for ways to improve reactor productivity and efficiency and to increase reactor safety. A concern that is closely regulated by the Nuclear Regulatory Commission is the exothermic zircaloy-steam oxidation reaction which can potentially occur during a loss of coolant accident (LOCA), and may become autocatalytic beyond 1,200 0C, thus generating a large amount of hydrogen. The concern for the zircaloy oxidation reaction has been heightened since the March 2011 events of Fukushima, Japan. One solution offering promising results is the use of silicon carbide (SiC) cladding in nuclear reactor fuel rod designs. SiC, a robust ceramic which reacts very slowly with water or steam, has many features that meet or exceed that of zircaloy including the ability to withstand higher temperatures due to a higher melting point and the ability to absorb fewer neutrons than zircaloy which would allow for increased safety margins and fuel burnup. An experimental investigation of the oxidation performance of a-SiC during a postulated LOCA event was performed. The test facility was designed and fabricated to test the oxidation rates of zircaloy and SiC in a high temperature, high-purity, flowing steam environment. Studies of zircaloy-4 oxidation were conducted to validate the test facility for this purpose. Thirty six zircaloy-4 tests lasting up to 30 minutes, at temperatures ranging from 800°C to 1,200°C, were completed and compared to existing models and literature data. Additionally, six longer duration a-SiC tests lasting from 8 hours to 48 hours, at temperatures of 1,140°C and 1,200°C, were completed. These tests clearly show that, from an oxidation perspective, SiC significantly outperforms zircaloy in high-flowing, superheated steam. For zircaloy, results from the most intense temperature/duration testing combination of 1,200°C for 30 minutes show 15.6 percent weight gain. For the most intense SiC tests at 1,200°C for eight hours, a weight loss of two orders of magnitude less occurred, a 0.077 percent weight loss. The four 24 hour and 48 hour SiC tests at 1,140°C also correlate well with the expected paralinear oxidation trend and further confirm that SiC is more resistant to oxidation in high temperature steam than zircaloy.
by Ramsey Paul Arnold.
S.M.
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Okeke, Joseph. "Pyrolysis of Agricultural Straw Using High Temperature Steam." Thesis, KTH, Materialvetenskap, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-37181.
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du, Preez Jean-Pierre. "Steam temperature and flow maldistribution in superheater headers." Master's thesis, Faculty of Engineering and the Built Environment, 2020. http://hdl.handle.net/11427/32230.
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Heat exchangers and steam headers are at the heart of any boiler and are susceptible to a range of failures including tube leaks, ligament cracking, creep and fatigue. These common forms of header failure mechanisms can be exacerbated by local thermal stresses due to temperature and flow maldistribution at full and partial boiler load operations. The purpose of this project is to develop process models of the outlet stubbox header of a final superheater (FSH) heat exchanger in a 620MW coal-fired drum type boiler. The process models were used to assess the impact of steam flow and temperature distribution on the thermal stresses in the header material. The process models were developed using Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA). Thermocouples were installed at key locations on the stubbox headers to monitor metal temperatures and the measured metal temperatures served as boundary values and for validation of the CFD results. The thermocouple data was analysed for three different steady state boiler loads, namely full load, 80% load and 60% load. It showed that the temperature distribution across these headers was not uniform, with a maximum temperature difference across the outlet stubbox of 40℃ at full load and 43℃ at partial loads. Other relevant power plant data, such as steam pressure, was provided from the power plant's Distributed Control System (DCS) and was used as boundary conditions for the CFD models. The exact mass flow distribution across the inlet stubs of the outlet stubbox header was unknown and was estimated using a CFD model of the inlet stubbox header and steam mass flow values from power plant's DCS system. A CFD model was created for each of the three boiler loads at steady state conditions. The CFD results provided the metal temperature profile, internal steam temperature distribution and pressure distribution across the header. The CFD solid temperatures were validated using the thermocouple readings and found to be in agreement. The CFD results were exported to the FEA models, where specific displacement constraints for thermal expansion were utilised. The FEA models were used to assess the extent of thermal stresses due to thermal expansion only, as well as stresses due to thermal expansion combined with internal pressure. High local stresses were found at the borehole crotch corners of the rear outlet branch and inlet stubs. However, these are below 0.2% proof strength at elevated temperatures. The high local stresses thus did not result in local plastic deformation but contribute to exacerbate steady state failure mechanisms such as creep.
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Vasic, Aleksander Z. "High temperature properties and heat transfer phenomena for steam at temperatures up to 5000K." Thesis, University of Ottawa (Canada), 1994. http://hdl.handle.net/10393/9641.
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Thermodynamic and transport properties and heat phenomena for steam in a high temperature region were examined. First, a set of computer subroutines was developed -the Fraction code, for generating molar fractions of a dissociating steam and gas mixture for a given pressure and temperature. Second, a set of computer subroutines was developed for the computation of all possible combinations of binary diffusion coefficients and of the diffusion coefficient for the component through a gas mixture. Third, steam properties may be evaluated for an ideal gas mixture which includes no effect of chemical reactions-frozed state, or for a non-ideal solution at equilibrium state which includes maximal effects of chemical reactions-effective properties at equilibrium state. A set of computer subroutines was developed-the Frozen Properties code, for evaluating dissociated steam frozen properties for a given pressure and temperature. A computer code, UODH2O (University of Ottawa Dissociation H$\sb2$O code), was developed using a look-up table and interpolation technique to generate effective properties at pressure from 0.01 to 100.00MPa and temperature from 1000 to 5726.85$\sp\circ$C. Based on the semi-empirical model by Nesterenko et al. (1967 a) for dissociated nitrogen tetroxide (N$\sb2$O$\sb4$#2NO$\sb2$ a two-component gas mixture), a method was developed to determine the Nusselt number of a chemically reacting (dissociated) fluid flow. (Abstract shortened by UMI.)
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Eccleston, Kelcey Lynne. "Solid oxide steam electrolysis for high temperature hydrogen production /." St Andrews, 2007. http://hdl.handle.net/10023/322.
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Eccleston, Kelcey L. "Solid oxide steam electrolysis for high temperature hydrogen production." Thesis, University of St Andrews, 2007. http://hdl.handle.net/10023/322.
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This study has focused on solid oxide electrolyser cells for high temperature steam electrolysis. Solid oxide electrolysis is the reverse operation of solid oxide fuel cells (SOFC), so many of the same component materials may be used. However, other electrode materials are of interest to improve performance and efficiency. In this work anode materials were investigated for use in solid oxide electrolysers. Perovskite materials of the form L₁₋ｘSrｘMO₃ , where M is Mn, Co, or Fe. LSM is a well understood electrode material for the SOFC. Under electrolysis operation LSM performed well and no interface reactions were observed between the anode and YSZ electrolyte. LSM has a relatively low conductivity and the electrode reaction is limited to the triple phase boundary regions. Mixed ionic-electronic conductors of LSCo and LSF were investigated, with these materials the anode reaction is not limited to triple phase boundaries. The LSCo anode had adherence problems in the electrolysis cells due to the thermal expansion coefficient mismatch with the YSZ electrolyte. The LSCo reacted with the YSZ at the anode/electrolyte interface forming insulating zirconate phases. Due to these issues the LSCo anode cells performed the poorest of the three. The performance of electrolysis cells with LSF anode exceeded both LSM and LSCo, particularly under steam operation, although an interface reaction between the LSF anode and YSZ electrolyte was observed. In addition to the anode material studies this work included the development of solid oxide electrolyser tubes from tape cast precursor materials. Tape casting is a cheap processing method, which allows for co-firing of all ceramic components. The design development resulted in a solid design, which can be fabricated reliably, and balances strength with performance. The design used LSM anode, YSZ electrolyte, and Ni-YSZ cathode materials but could easily be adapted for the use of other component materials. Proper sintering rates, cathode tape formulation, tube length, tape thickness, and electrolyte thickness were factors explored in this work to improve the electrolyser tubes.
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Bapeekee, Sulaiman Ahmed Sadeck. "Determining internal leakages of high pressure and temperature steam valves." Master's thesis, University of Cape Town, 2015. http://hdl.handle.net/11427/24314.
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Internal leakages of high pressure and temperature steam valves have been identified as a potential contributor to a loss in power generating plant efficiency. These losses are often neglected due to it being difficult to detect problematic valves and quantify the internal leakages through them. A non-intrusive NOT technique that detects and quantifies internal leakages through valves will be a very favourable tool to any power generating plant as it will allow for the early detection of internal leakages and could possibly provide considerable financial savings. This research evaluates different monitoring techniques suitable for detecting and quantifying internal leakages through valves and selects a technique that is most suitable for application in a power generating plant environment. The proposed technique utilises infra-red thermography to calculate pipe surface temperatures on a length of un-insulated pipe located downstream of a valve that is leaking internally. As the leakage steam flows through the length of un-insulated pipe, it will lose a portion of its heat energy through the pipe wall to the surrounding environment. This will result in a drop in temperature of the steam from the upstream to downstream points of the un-insulated length of pipe. By calculating the heat loss and the drop in temperature of the leakage steam, a mass flow rate of the leakage steam can be determined. A mathematical model was derived which with inputs of upstream and downstream pipe surface temperatures of the un-insulated pipe, pipe properties and ambient air conditions, calculates the heat loss, the temperature drop and the resulting mass flow rate of the leakage flow through the valve. A detailed experimental study was conducted to validate the proposed technique in determining internal leakages thought steam valves. Steam generated from a mini steam generating plant was allowed to flow through an experimental test rig, which contained a length of un-insulated pipe, at different flow rates. Pipe surface temperature measurements of the un-insulated pipe were made using an infrared thermal camera and a mass flow rate of the steam was calculated using the derived mathematical model. In all experiments, the mass flow rate calculated using the mathematical model was compared to a mass flow rate acquired from a flow measuring device installed in-line with the experimental test rig. The results indicate that an increase in mass flow rate causes an increase in pipe surface temperatures of the un-insulated pipe which translates to an increase in heat loss of the leakage steam through the length of un-insulated pipe. The mass flow rate calculated using the proposed technique closely approximates the mass flow rate acquired from the flow measuring device. This indicates that the proposed technique, using infrared thermography, is capable of detecting and quantifying possible internal valve leakages encountered in online operation. Onsite tests were performed using the proposed technique on two different boiler drain valves at Majuba Power Station. It was found that one of the valves was internally leaking steam to the atmosphere at a rate of 0.039 kg/s whilst the other valve was sealing correctly. A comprehensive financial impact study was conducted, and it was found that this leakage steam will result in a total loss of R 730 108 per annum if the leak is left unattended. This is the loss for a single valve that has a relatively small leak. The financial loss for a combination of all valves that are internally leaking in a power plant could be substantial and can clearly justify plant personnel in utilising the proposed technique to identify problematic valves. With its portability, non-intrusiveness and ease of use the proposed technique provides a cost-effective means to determine internal leakages through power plant valves.
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Waite, Jason S. "The application of brush seals to steam turbine generators." Thesis, Northumbria University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367419.
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Harrington, M. T. "Oxide growth on ferritic stainless steels exposed to high temperature steam." Thesis, University of Manchester, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233277.
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Arif, Muhammad Jalil. "High Temperature Air/Steam Gasification (HTAG) Of Biomass – Influence of Air/Steam flow rate in a Continuous Updraft Gasifier." Thesis, KTH, Materialvetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-119835.
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Biomass is an important source of energy and the most important fuel worldwide after coal, oil and natural gas. Biomass does not add carbon dioxide to the atmosphere as it absorbs the same amount of carbon in growing as it releases when consumed as a fuel. Its advantage is that it can be used to generate electricity with the same equipment or power plants that are now burning fossil fuels. However, the low energy density of the biomass requires developments and advances in conversion technologies in order to increase process efficiency and reduce pollution. One of the most promising converting methods for treatment of biomass and waste feedstock is gasification. In this study a highly preheated air/steam of temperatures >800oC is introduced to the gasifier which is fed with wood pellets’ feeding rate 40-50 kg/h. The system is redesigned to work as a continuous type updraft HTAG. The aim of the studies was to test the performance of an Updraft configuration in various operating conditions using Biomass (wood pellets) as the feedstock, and facing primarily technological difficulties and process limitations. Determining the Temperature distribution along the reactor and synthesis gas composition of the process are reported for various operating parameters. During the experiment it is observed that the introduction of more steam flow rate increases the LHV (lower heating value) of the synthesis gases. Three case studies (Case1, Case2, and Case3) are conducted, each case having different biomass feeding rate, steam flow rate and process air flow rate. The result show that the amount of LHV of gas varied from 3 to 4.2 MJ/Nm3, the H2: CO ratio is between 0.5-0.9 and the CO/CO2 ratio has range 1.0-1.7. Case 3, in which 40 kg/h biomass feeding rate and 80 kg/h Steam flow rate is maintained gives High LHV, high H2/CO ratio and more CO/CO2 ratio among the rest case studies. Further improvement can be done within the reactor, increase in retention time and variation of more parameters can examine, in order to get the optimum result in future.
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Lukaszewicz, Mikolaj. "Steam oxidation of advanced high temperature resistant alloys for ultra-supercritical applications." Thesis, Cranfield University, 2012. http://dspace.lib.cranfield.ac.uk/handle/1826/7917.
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Steam oxidation of heat exchanger tubing is of growing interest as increasing the efficiencies of conventional pulverised fuel fired power plants requires higher steam temperatures and pressures. These new, more severe steam conditions result in faster steam oxidation reactions, which can significantly reduce the lifetime of boiler components. This thesis reports results from an investigation of the steam oxidation of the high temperature resistant alloys. It covers an analysis of the impact of temperature, steam flow rate, specimen shape and specimen surface finish on oxidation of resistant materials. Additionally, the mechanism of steam oxidation was invastigated with the oxygen 18 water. The results show that an increased steam flow rate not only causes faster oxidation rates but also a change in oxide scale morphology. In case of T23, it triggers formation of micro-layered inner oxide, whereas for T92 it promotes the formation of an outer haematite layer. For austenitic steels, the faster steam flow increases the formation of initially protective oxide scales, but also accelerates the growth of oxide nodules with prolonged exposure times. The analysis of the different surface finishes show that clearly the change of the surface finish from ground to polish and pickled (as received) accelerates the oxidation process for austenitic steels, the ground specimens show the slowest oxidation, whereas the pickled specimens oxidise much faster and form thicker scales. Finally, the study of oxidation mechanism show that steam oxidation is not only controlled by the inner diffusion of the oxygen ions but the diffusion of the hydroxides have a significant impact on oxides formation. The results of the study suggest that the hydroxide ions influence formation of the inner oxides.
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Alevanau, Aliaksandr. "Study of the Apparent Kinetics of Biomass Gasification Using High-Temperature Steam." Licentiate thesis, KTH, Energi- och ugnsteknik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-26356.
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Among the latest achievements in gasification technology, one may list the development of a method to preheat gasification agents using switched ceramic honey combs. The best output from this technology is achieved with use of water steam as a gasification agent, which is heated up to 1600 °C. The application of these temperatures with steam as a gasification agent provides a cleaner syngas (no nitrogen from air, cracked tars) and the ash melts into easily utilised glass-like sludge. High hydrogen content in output gas is also favourable for end-user applications.Among the other advantages of this technology is the presumable application of fixed-bed-type reactors fed by separately produced and preheated steam. This construction assumes relatively high steam flow rates to deliver the heat needed for endothermic reactions involving biomass. The biomass is to be heated uniformly and evenly in the volume of the whole reactor, providing easier and simpler control and operation in comparison to other types of reactors. To provide potential constructors and exploiters of these reactors with the kinetic data needed for the calculations of vital parameters for both reactor construction and exploitation, basic experimental research of high-temperature steam gasification of four types of industrially produced biomass has been conducted.Kinetic data have been obtained for straw and wood pellets, wood-chip charcoal and compressed charcoal of mixed origin. Experiments were conducted using two experimental facilities at the Energy and Furnace Division of the Department of Material Science and Engineering (MSE) at the School of Industrial Engineering and Management (ITM) of the Royal Institute of Technology (KTH) and at the Combustion Laboratory of the Mechanical Engineering Department of the University of Maryland (UMD), USA. The experimental facility at the Energy and Furnace Division has been improved with the addition of several constructive elements, providing better possibilities for thermo-gravimetric measurements.The obtained thermo-gravimetric data were analysed and approximated using several models described in the literature. In addition, appropriate software based on the Scilab package was developed. The implementation of the isothermal method based on optimisation algorithms has been developed and tested on the data obtained under the conditions of a slow decrease of temperature in experiments with the char gasification in small-scale experimental facilities in the Energy and Furnace Division.The composition of the gases generated during the gasification of straw and wood pellets by high-temperature steam has been recorded and analysed for different experimental conditions.QC 20101124
Study of ignition and kinetics of biomass/solid waste thermal conversion with high-temperature air/steam
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Smith, Alan. "The effects of inlet water temperature on condensing film coefficients /." Online version of thesis, 1995. http://hdl.handle.net/1850/11923.
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Reyes, Salvador Byron Fernando. "DEVELOPMENT OF A HIGH-PRESSURE, HIGH-TEMPERATURE SUPERHEATED STEAM SYSTEM (WATER TREATMENT, VAPORIZER, THERMAL DESIGN, MODELING)." Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/275460.
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Nyawo, Talent. "Design of a rotary valve for pressurised steam." Thesis, KTH, Maskinkonstruktion (Inst.), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-192859.
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Denna rapport är gjord på ett examensarbete som var utfört på uppdrag av det svenska företaget Ranotor AB. Syftet var att utveckla en konceptuell lösning för en rotationsventil som skall fungera i en miljö med hög temperatur och högt tryck. Ventilen skall arbeta under höga rotationshastigheter, vilket kräver korta öppettider.Tekniska hjälpmedel såsom SolidWorks, ANSYS och MATLAB användes för att modellera och analysera de konceptuella lösningarna. Slutlösningen valdes från ett flertal olika koncept, varpå detta vidareutvecklades och optimerades. Betydande material och gastätningslösningar identifierades och utvärderades för att hitta den bästa lösningen. Optimering av individuella komponenter och hela anordningen gjordes med avseende på spänning, termisk- och dynamisk analys. De givna specifikationerna uppfylldes och resultaten var tillfredsställande. Resultaten ger en teoretisk bas för vidareutveckling och applicering av en rotationsventil in en miljö med hög temperatur och högt tryck.This Master thesis is a project commissioned by the Swedish company Ranotor AB. The objective of this thesis is to develop a conceptual solution for a rotary valve mechanism that has to work efficiently in a high-temperature and high-pressure environment. The valve is to operate at high rotational speeds which calls for very short opening time.Modern engineering tools namely Solidworks, Ansys and Matlab, were employed for modelling and analysis of the conceptual solution.The best design solution was selected from three developed concepts, and the selected concept was further developed and optimized. Major material candidates and gas-tight sealing solution were identified and evaluated and the optimal material and seal design was chosen. Optimization of the individual components as well as the whole assembly was performed based on stress, thermal and dynamic analysis. The given design specifications and functions were fulfilled and the results were satisfactory. The obtained results provide a theoretical foundation for the development and application of a rotary valve in high-temperature and high-pressure environment.
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Cong, Ngoc Thang. "Adsorption enhanced steam methane reforming for low temperature hydrogen production using solids circulation." Thesis, University of Leeds, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.509040.
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Stuart, Paul Anthony. "The synthesis and evaluation of proton conducting electrolytes for high temperature steam electrolysers." Thesis, Imperial College London, 2010. http://hdl.handle.net/10044/1/5571.
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Proton conducting ceramics based on acceptor doped perovskites are the subject of investigation as candidate electrolyte materials for Solid Oxide Electrolyser Cells (SOECs). Specifically, BaCe0.9Y0.1O3-[delta](BCY10) and BaZr0.9Y0.1O3-[delta](BZY10) were investigated. Samples with greater than 95% of the maximum theoretical density were successfully prepared using a BCY10 commercial powder. It was found that when small additions of ZnO were added to a BZY10 commercial powder, a density of greater than 95% of the theoretical maximum was achievable whereas without ZnO addition, the maximum achievable density was 85%. BCY10 was found to have a total conductivity approximately one order of magnitude greater than Zndoped BZY10 over the entire temperature range studied. Spray pyrolysis and sol-gel methods were used successfully to prepare single phase pure BZY10 powders. The sintering behaviours of the powders produced by spray pyrolysis were found to alter significantly with changes in powder processing parameters. BCY10 and Zn-doped BZY10 cells were tested in electrolysis and fuel cell modes and the effects of varying operating conditions on cell performances were studied. At 750oC, the Area Specific Resistances (ASR) of a BCY10 cell in electrolysis mode was found to be lower when the anode compartment was humidified to [approximately equal]83% than to[approximately equal]3%. Below this temperature, ASR values were greater when using increased humidity levels. It was concluded that a degree of oxide ion conduction may be beneficial to the operation of proton conducting electrolysers. Post-test, BCY10 cell cross-sections were imaged using scanning electron microscopy and analysed using Energy Dispersive X-ray (EDX) spectroscopy. Significant erosion of grain boundaries regions close the electrode-electrolyte interfaces was observed and EDX spectroscopy results suggested the formation of a secondary phase in these regions, possibly Y:CeO2. Had testing continued over an extended period of time it is probable that BCY10 cells would have undergone mechanical failure.
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Chinyanganya, Farai W. "Studies on potential biological indicator organisms for low temperature steam and formaldehyde (LTSF) sterilization." Thesis, University of Bath, 1989. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.760590.
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Di, Jiexun. "Development of highly active internal steam methane reforming catalysts for intermediate temperature solid oxide fuel cells." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:a36ce531-e7b2-48fb-a59b-dbca6b435643.
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Fuel processing is one of the essential parts for development of intermediate solid oxide fuel cells (IT-SOFC). Natural gas (methane) is considered as the most abundant and cost effective fuel for the production of hydrogen for IT-SOFC. The primary aim of this thesis is to use a novel precursor material—layered double hydroxide (LDH) – for developing a new type of cost effective, highly active and long lasting catalyst which can reform natural gas in IT-SOFC anode environment. Small amount of noble metals Pd, Rh and Pt are used as promoters to enhance the catalyst’s performance as while maintaining the cost relatively low. The research objectives are achieved by a series of studies including catalysts synthesis, characterisation and the catalytic activities. The thesis initially gives a comprehensive review on fuel cell and SOFC technology, steam methane reforming and reforming catalyst to provide better understanding of the research. Experimental studies include the effects of the synthetic conditions of the LDH precursors and thermal treatments on the physical, chemical behaviours and catalytic activities of the catalysts and promotional effects by noble metals. The LDH derived catalysts compositions, promoter quantities and operating conditions are optimised for the best performance in the IT-SOFC anode environment. A new method for the development of precursor sol for easy coating of the anode is developed and studied. The sol preparation is achieved by acid attack. The sol developed is found to produce better coating and has very high catalytic properties after activation. The catalysts developed were tested for their stability and self-activation ability to ensure its use in the commercial cells. The findings of the present study indicate that the catalysts developed show excellent catalytic performance and these catalysts have very high potential for further commercialisation in IT-SOFC.
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Yap, Mun Roy. "Biomass Integrated Gasification Combined Cycles (BIGCC)." ScholarWorks@UNO, 2004. http://scholarworks.uno.edu/td/206.
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Conversion of biomass to energy does not contribute to the net increase of carbon dioxide in the environment, therefore the use of biomass waste as a clean and renewable fuel source is an attractive alternative to the use of fossil fuels. Biomass can be converted to energy via direct combustion or via thermo-chemical conversion to liquid or gas fuels. This study focuses on employing gasification technology to convert biomass waste to producer gas, which is then cleaned and fed as gaseous fuel into the gas turbine. Since the producer gases are usually low caloric values, the power plants performance under various operating conditions has not yet been proven. In this study, system performance calculations are conducted for a 5MWe and a 20MWe power plants using commercial software ThermoFlow. The power plants considered including simple gas turbine systems, steam turbine systems, combined cycle systems, and steam injection gas turbine systems (STIG) using the producer gas with low caloric values at approximately 30% and 15% of the natural gas heating value. The low caloric value fuels are shown to impose high back compressor pressure and increased power output due to increased fuel flow. Power augmentations under four different weather conditions are also calculated by employing gas turbine inlet fog cooling. Different capacity options for the heat recovery steam generator (HRSG) that provides the steam for STIG are analyzed.
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Pratašius, Darius. "Terminės piktžolių kontrolės vandens garu poveikis dirvožemio organinės medžiagos pokyčiams." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2014. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2014~D_20140616_132526-31456.
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Magistriniame darbe tiriama terminė piktžolių kontrolė vandens garu, kuri yra viena iš aplinką tausojančių technologijų pasėlių piktžolėtumui mažinti. Iki šiol buvo tirtas vandens garo poveikis augalui, atlikti kai kurie temperatūros sklaidos termiškai paveiktame dirvožemio sluoksnyje tyrimai, tačiau poveikis dirvožemio ekosistemai ir jo kokybei nebuvo tirtas.This Master's thesis investigated thermal weed control by water steam which is green and efficient technology for crop protection. Until now studies of the water steam effect on plants, also some measurements of the temperature spread in soil were performed, however impact on soil ecosystem and its quality has not been studied.
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Mahato, Raman. "Kinetic modeling of low temperature catalytic steam gasification of Powder River Basin coal and petcoke /." Available to subscribers only, 2007. http://proquest.umi.com/pqdweb?did=1324367701&sid=11&Fmt=2&clientId=1509&RQT=309&VName=PQD.
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Thesis (M.S.)--Southern Illinois University Carbondale, 2007."Department of Mechanical Engineering and Energy Processes." Includes bibliographical references (leaves 53-54). Also available online.
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Lucas, Carlos. "High temperature air/steam gasification of biomass in an updraft fixed bed batch type gasifier." Doctoral thesis, Stockholm, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-224.
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Radfarnia, Hamid Reza. "High-temperature CO2 sorbents and application in the sorption enhanced steam reforming for hydrogen production." Thesis, Université Laval, 2013. http://www.theses.ulaval.ca/2013/30465/30465.pdf.
Full textAbstract:
Le reformage à la vapeur couplé à la sorption in-situ d’un composant du milieu réactionnel (sorption-enhanced steam reforming, SESR) est un procédé d’avant-garde qui permet simultanément la production d’hydrogène de très haute pureté et la capture du CO2. L'objectif principal de ce travail est le développement de nouveaux sorbants pour le CO2 applicables à hautes températures et l’étude de leur application dans SESR. Deux nouvelles méthodes de synthèse ont été proposées pour synthétiser du zirconate de lithium (Li2ZrO3), zirconate de sodium (Na2ZrO3) ainsi que des matériaux à base d’oxyde de calcium (CaO), trois catégories de sorbants capables de réagir avec le CO2 à hautes températures. L’application du Li2ZrO3 à la capture du CO2 a démontré une augmentation de l’activité du matériau produit par une nouvelle méthode de synthèse combinant un surfactant et traitement à ultrasons, comparativement au Li2ZrO3 préparé par une méthode avec surfactant seulement (sans ultrasons) ou par la méthode conventionnelle (mélange des composants en phase liquide). Néanmoins, pour des pressions partielles en CO2 inférieures à 0,75 bar, la faible cinétique de sorption du CO2 obtenue par le Li2ZrO3 limite son application au procédé SESR. En considérant l’amélioration des propriétés de sorption obtenue en appliquant la méthode combinée surfactant/ultrasons à la synthèse du Li2ZrO3, la même technique a été aussi appliquée à la synthèse du Na2ZrO3. Des résultats inattendus ont été pourtant obtenus. Le Na2ZrO3 développé par la nouvelle technique a été moins actif durant les cycles sorption/régénération que celui produit par la méthode conventionnelle, de par la faible résistance de sa structure poreuse à de très hautes températures. La nouvelle méthode de synthèse combinée surfactant/ultrasons a été aussi appliquée pour la synthèse de CaO stabilisé par du zirconium (Zr). Un rapport Zr/Ca de 0,303 a été trouvé optimal pour la production d’un sorbant présentant la meilleure stabilité et activité pour la capture de CO2. Dans les conditions sévères d’opération, les résultats ont généralement indiqué une capacité de sorption du CaO stabilisé supérieure à celle du CaO pure. Dans le but de réduire les coûts de production des sorbants, une source moins chère de CaO (calcaire naturel) a été utilisée en combinaison avec une nouvelle méthode de synthèse qui consiste dans l’acidification du calcaire par de l’acide citrique suivie par une calcination en deux étapes (argon et air). Doté d’une structure hautement poreuse, le CaO produit a révélé une stabilité nettement meilleure par rapport au calcaire, ainsi qu’une capacité accrue de sorption du CO2. La même technique de synthèse a été aussi utilisée pour développer plusieurs matériaux à base de CaO stabilisé par divers oxydes métalliques (Al, Zr, Mg et Y), afin d’améliorer la stabilité du sorbant dans les conditions opérationnelles sévères, particulièrement les hautes températures de régénération en présence de CO2. CaO stabilisé par l’aluminium (Al) ou le zirconium (Zr) a démontré une meilleure activité comparativement aux autres matériaux synthétisés, inclusivement dans des conditions sévères d’opération. L’application de ces deux types de sorbants au vaporeformage du méthane (SESMR) a été ensuite étudiée dans un réacteur à lit fixe. Pour minimiser les limitations diffusionnelles, deux matériaux hybrides sorbant-catalyseur ont été développés. NiO-CaO stabilisé par Zr, préparé par la méthode combinée surfactant/ultrasons, dont le contenu en NiO est de 20.5 % (masse) a montré une efficacité dans la production d’hydrogène de 92% lors du premier cycle de reformage, ce qui est remarquablement plus élevée que le rendement d’équilibre en H2 pour le procédé traditionnel de vaporeformage du méthane (SMR) ( 70%). La méthode acidification/calcination en deux étapes a été utilisée pour produire le deuxième matériau hybride (NiO-CaO stabilisé par Al). L’application du matériau contenant 25 % (masse) de NiO a conduit à une efficacité moyenne de production d’hydrogène de 97.3%, démontrant ainsi son grand potentiel pour le SESMR. Les résultats de ce projet de recherche ont clairement démontré que le procédé SESR est une alternative très avantageuse au procédé traditionnel de reformage à la vapeur (sans séparation in-situ de CO2) pour la production d’hydrogène de très haute pureté. Le matériau hybride sorbant-catalyseur NiO-CaO stabilisé par Al a démontré une excellente activité à long terme, en confirmant son potentiel élevé pour application dans le procédé SESMR.Sorption-enhanced steam reforming (SESR) is a forefront technology to produce H2 clean fuel, which integrates both CO2 capture and H2 production in a single process. The main objective of this work is to develop novel high-temperature CO2 sorbents and to investigate their application in SESR operation. Special attention was given to lithium zirconate (Li2ZrO3), sodium zirconate (Na2ZrO3) and calcium oxide (CaO)-based materials, as most famous high temperature CO2 sorbents, by applying two novel synthesis techniques. The application of Li2ZrO3 in CO2 capture sorption showed an increase in activity of the material prepared by surfactant template/sonication method compared to Li2ZrO3 prepared by simple surfactant template method (without sonication) or conventional wet-mixing route. Nevertheless, porous Li2ZrO3 still suffered from slow kinetics of CO2 sorption at low CO2 partial pressure (below 0.75 bar), which can limit its application for SESMR operation. Taking into consideration the improvement of Li2ZrO3 sorption properties, the same surfactant template/sonication technique was then applied to develop porous Na2ZrO3. The behavior of the new developed Na2ZrO3 was unexpected. The samples prepared by surfactant template/sonication technique were found to be less active than the conventional Na2ZrO3 during cyclic operation, due to the low resistivity of the pore structure at the very high temperature treatment required for calcination. The same surfactant template/sonication was also applied to develop Zr-stabilized CaO sorbents. An optimum Zr/Ca ratio of 0.303 was found to maximize the stability and CO2 capture activity of the proposed Zr-stabilized CaO sorbent. The results generally showed a better CO2 capture ability of Zr-stabilized CaO sorbent in comparison with pure CaO in severe cyclic operating conditions. With the purpose of reducing the cost of sorbent production, a cheaper source of CaO (natural limestone) was also considered and a novel synthesis technique (limestone acidification by citric acid followed by two-step calcination (in Ar and air atmospheres)) was applied in order to prepare highly porous CaO structure with unique CO2 capture ability. The results revealed a much better stability and CO2 sorption activity of the developed sorbent compared to natural limestone. The same technique was employed to develop a number of metal oxide (Al, Zr, Mg and Y)-stabilized CaO sorbents in order to enhance sorbent stability in severe operating conditions, i.e., high temperature regeneration in the presence of CO2. Al and Zr-stabilized CaO showed the best activity during both mild and severe operating conditions. The performance of the developed CO2 sorbents providing the best performance in CO2 capture (Zr-stabilized and Al-stabilized CaO) were then investigated experimentally in the sorption enhanced steam methane reforming (SESMR) using a fixed-bed reactor. To minimize the diffusional limitations, a hybrid catalyst-sorbent was developed for both sorbents. The application of Zr-stabilized CaO-nickel hybrid catalyst with 20.5 wt% NiO loading, prepared by surfactant-template/sonication method, resulted in 92% H2 production efficiency for the initial SESMR cycle, which is remarkably higher than traditional steam methane reforming (SMR) equilibrium H2 yield (70 %). The second developed hybrid sorbent-catalyst (Al-stabilized CaO-NiO) was prepared using limestone acidification coupled with two-step calcination technique. The long-term application of the hybrid catalyst containing 25 wt% NiO led to an average H2 production efficiency of 97.3%, proving its high efficiency in the SESMR process. In summary, the results of this thesis show that the SESR process is as an efficient alternative of traditional steam reforming for production of highly pure H2. The Al-stabilized CaO-NiO hybrid sorbent-catalyst showed an excellent activity over long-term operation, thus confirming its very high potential for use in the SESMR process.
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Qadri, Syed N. "Development of a double-layered perovskite as alternative anode material for high temperature steam electrolysis." Thesis, University of St Andrews, 2014. http://hdl.handle.net/10023/5826.
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The research presented is based on alternative anode materials for high temperature steam electrolysis. The key to commercially viable renewable energy economy is based on energy storage of intermittent sources. Hydrogen is the preferred form of energy storage for solid oxide electrolysis cells. However, conventional anode material lanthanum strontium manganite (LSM), suffers from poor ionic conductivity, thus prohibiting much of the bulk electrode from providing an enhanced electrochemical performance. This study explores the use of a double-layered perovskite system with mixed electronic and ionic conductivity for use as anode material. Specifically, the SmBa₁₋ₓSrₓCo₂O[sub](5+δ) system (SBSCO) is analyzed for characteristics that may enhance the performance and feasibility of SBSCO as an alternative anode material to LSM. Previous in-house work showed SmBa₀.₅Sr₀.₅Co₂O[sub](5+δ) had the lowest area specific resistance of any double- layered material reported. Here the system is further explored by studying the full range of compositions. From X-ray diffraction analysis, increased Sr substitution leads to a tetragonal phase change in SBSCO. High temperature x-ray diffraction of compositions showed thermal stability of structure. Magnetization measurements are reported for selected compositions. The stability of SBSCO was examined in CO₂ containing atmospheres. Despite containing alkaline earth metals, the system offers limited CO₂ tolerance. A set of thermodynamic parameters is presented based on CO₂ partial pressure and temperature. Model indicates SBSCO is a stable electrode material for both electrolysis and fuel cell modes. Compositions were tested for steam electrolysis performance with the use of YSZ electrolyte, and Ni-YSZ and La₀.₄Sr₀.₄Ni₀.₀₆Ti₀.₉₄O₂.₉₄ cathodes. SmBa₀.₃Sr₀.₇Co₂O[sub](5+δ) had the highest performance for compositions (0≤x≤1) based on I-V curves and impedance measurements. Stability tests were conducted in potentiostatic mode and no delamination was observed for SBSCO in microstructural analysis after testing. From these studies, SBSCO is demonstrated to be a suitable for application in electrolysis and an alternative for LSM as anode material.
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Azeez, Ahmed. "High-Temperature Fatigue in a Steam Turbine Steel : Modelling of Cyclic Deformation and Crack Closure." Licentiate thesis, Linköpings universitet, Mekanik och hållfasthetslära, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-173354.
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Existing conventional thermal power plants are retrofitted for flexible operations to assist the transition toward more renewable energies. The deployment of many renewable energy power plants is necessary to achieve a clean environment with less pollution. However, the intermittent nature of renewable energies, due to weather changes, and the lack of efficient large energy storage systems put renewables at a disadvantage. Flexible operations of power plants imply fast and frequent start-ups. Thus, retrofitted power production plants can be utilised as an energy backup to satisfy the immediate demand during peak energy times or when renewable energies are suddenly limited. Large thermal power plants generally employ steam turbines with high inlet temperature and pressure steam conditions. Materials used for components at the high-temperature turbine sections are expected to withstand harsh environments. The use of 9-12 % Cr martensitic steels is desirable due to, among other things, their superior resistance to creep for temperatures up to 625 °C. Retrofitting for flexible operations put steam turbine components under high-temperature fatigue loading conditions different from how they were designed before. The flexible operations could lead to fatigue cracking at critical locations, such as grooves and notches at the inner steam turbine casing. Thus, fatigue behaviour understanding of steam turbine materials under such loading conditions is essential for components life prediction. Accurate and less conservative fatigue life prediction approach is necessary to extend the turbine components life, which reduces waste and provides economic benefits. This can be done by extending operations past crack initiation phase and allowing controlled propagation of cracks in the components. Within the 9-12 % Cr steel class, the martensitic steam turbine steel called FB2 is studied under high-temperature fatigue. This includes investigating high-temperature fatigue life behaviour, cyclic deformation behaviour, stress relaxation behaviour, and crack propagation behaviour along with crack closure behaviour. This was achieved by experimentally testing samples made from FB2 steel under isothermal low cycle fatigue, isothermal fatigue crack propagation, and thermomechanical fatigue crack propagation.
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Shen, Chih Hao. "Mechanisms of hydrogen induced intergranular stress corrosion cracking of Alloy 600 in high temperature water/steam /." The Ohio State University, 1989. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487599963590661.
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Lindsay, John Christopher. "Stress corrosion cracking and internal oxidation of alloy 600 in high temperature hydrogenated steam and water." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/stress-corrosion-cracking-and-internal-oxidation-of-alloy-600-in-high-temperature-hydrogenated-steam-and-water(1d6b037c-baf1-4397-a6c9-43835e7bb39a).html.
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In this study, the possibility of using low pressure hydrogenated steam to simulate primary water reactor conditions is examined. The oxides formed on Alloy 600 (WF675) between 350 Celsius and 500 Celsius in low pressure hydrogenated steam (with a ratio of oxygen at the Ni/NiO to oxygen in the system of 20) have been characterised using analytical electron microscopy (AEM) and compared to oxide that formed in a high pressure water in a autoclave at 350 Celsius with 30 cc/kg of hydrogen. Preferential oxidation of grain boundaries and bulk internal oxidation were observed on samples prepared by oxide polishing suspension (OPS). Conversely, samples mechanically ground to 600 grit produced a continuous, protective oxide film which suppressed the preferential and internal oxidation. The surface preparation changed the form of the oxides in both steam and autoclave tests. The preferential oxidation rate has been determined to be K_{oxide} = Aexp{-Q/RT}with A = 2.27×10^(−3) m^(2)s^(−1) and Q = 221 kJ.mol^(−1) (activation energy) for WF675 and A = 5.04 × 10^(−7) m^(2)s^(−1) and Q = 171 kJ.mol^(−1) for 15% cold worked WF675. These values are consistent with the activation energy of primary water stress corrosion cracking (PWSCC) initiation. Bulk oxygen diffusivities were calculated from the internal oxidation after 500 h exposures. At 500 Celsius the oxygen diffusivity was determined to be 1.79×10^(−20) m^(2)s^(−1) for WF675 and 1.21×10^(−20) m^(2)s^(−1) for 15% cold worked WF675, the oxygen diffusivity at 400 Celsius in 15% cold worked WF675 was calculated to be 1.49×10^(−22) m^(2)s^(−1).The Cr-depletion associated with preferential oxidation has been assessed by AEM. The Cr-depletion was asymmetric and it could not be accounted for by local variations in the diffusion rate. Chemically induced grain boundary migration is suggested as a possible explanation. Constant load SCC tests conducted in hydrogenated steam at 400 Celsius have shown a similar trend to the classical dependency of PWSCC as a function of potential. The SCC samples were also prepared with two surface finishes, OPS and 600 grit. In all SCC tests, significantly more cracking was observed on the OPS surface and all failures initiated from this surface.
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Udagawa, Jun. "Hydrogen production through steam electrolysis : model-based evaluation of an intermediate temperature solid oxide electrolysis cell." Thesis, Imperial College London, 2008. http://hdl.handle.net/10044/1/8310.
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Steam electrolysis using a solid oxide electrolysis cell at elevated temperatures might offer a solution to high electrical energy consumption associated with conventional water electrolysers through a combination of favourable thermodynamics and kinetics. Although the solid oxide electrolysis cell has not. received significant attention over the past several decades and is yet to be commercialised, there has been an increased interest towards such a technology in recent years, aimed at reducing the cost of electrolytic hydrogen. Here, a one-dimensional dynamic model of a planar cathode-supported intermediate temperature solid oxide electrolysis cell stack has' been developed to investigate the potential for hydrogen production using such an electrolyser. Steady state simulations have indicated that the electrical energy consumption of the modelled stack is significantly lower than those of water electrolysers commercially available today. However, the dependence of stack temperature on the operating point has suggested that there is a need for temperature control. Analysis of a possible temperature control strategy by variation of the air flow rate through the stack has shown that the resulting changes in the convective heat transfer between the air flow and stack can alter the stack temperature. Furthermore, simulated transient responses indicated that manipulation of such an air flow rate can reduce stack temperature excursions during dynamic operation, suggesting that the p,oposed control strategy. has a good potential to prevent issues related to the stack temperature fluctuations.
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Jongschaap, Tiemen, and Rick Smit. "Camera cleaning study for Automatic Milking System utilizing steam at DeLaval International AB." Thesis, Linnéuniversitetet, Institutionen för maskinteknik (MT), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-27028.
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The VMS is a robot milking system of DeLaval International AB. It has been observed that a layer of residue remains on the camera lens after cleaning. The camera is used to locate the teat and apply the milking cups. Even though after automatically cleaning with a sponge, it is very difficult to remove this layer. This study has been conducted to find out if a new cleaning station utilizing steam can have better cleaning results concerning the mentioned problem. A test setup was built to perform several tests. The boiler is capable to supply steady steam with the same pressure and temperature every milking cycle, which is approximately 8 minutes. Tests further on showed that the inside camera housing temperature not exceed 35°C, which remains under the required limit of 50°C. After the steam has cleaned the lens compressed blows and cools the remaining droplets left behind. The comparison between the sponge and the steam cleaning method confirms that the steam cleaning method is able to remove the contaminations more sufficient than the sponge. One of the contaminations is milk which is the worst kind. Studies showed that milk tends to denaturize when heated above 60°C. This could form a layer of burned proteins on the lens.
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Hüttel, Thomas [Verfasser]. "Investigation of the high temperature performance of thermal barrier coating systems for steam turbine applications / Thomas Hüttel." Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2011. http://d-nb.info/1018200185/34.
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Cory, N. J. "The hydrogen emission and kinetics of the high temperature oxidation of ferritic steels by super-heated steam." Thesis, University of Reading, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381910.
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Wright, Andrew M. "Selection, production and characterisation of a biological indicator organism for low temperature steam and formaldehyde (LTSF) sterilization." Thesis, University of Bath, 1991. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.279300.
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Wang, Alan Yao. "Steam Reactivation and Separation of Limestone Sorbents for High Temperature Post-combustion CO2 Capture from Flue Gas." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1342457128.
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Barner, Robert Buckner. "Power conversion unit studies for the next generation nuclear plant coupled to a high-temperature steam electrolysis facility." Texas A&M University, 2006. http://hdl.handle.net/1969.1/4835.
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The Department of Energy and the Idaho National Laboratory are developing a
Next Generation Nuclear Plant (NGNP) to serve as a demonstration of state-of-the-art
nuclear technology. The purpose of the demonstration is two fold: 1) efficient low cost
energy generation and 2) hydrogen production. Although a next generation plant could
be developed as a single-purpose facility, early designs are expected to be dual-purpose.
While hydrogen production and advanced energy cycles are still in their early stages of
development, research towards coupling a high temperature reactor, electrical generation
and hydrogen production is under way. Many aspects of the NGNP must be researched
and developed to make recommendations on the final design of the plant. Parameters
such as working conditions, cycle components, working fluids, and power conversion
unit configurations must be understood.
Three configurations of the power conversion unit were modeled using the
process code HYSYS; a three-shaft design with 3 turbines and 4 compressors, a
combined cycle with a Brayton top cycle and a Rankine bottoming cycle, and a reheated
cycle with 3 stages of reheat were investigated. A high temperature steam electrolysis
hydrogen production plant was coupled to the reactor and power conversion unit by
means of an intermediate heat transport loop. Helium, CO2, and an 80% nitrogen, 20%
helium mixture (by weight) were studied to determine the best working fluid in terms
cycle efficiency and development cost. In each of these configurations the relative heat
exchanger size and turbomachinery work were estimated for the different working fluids. Parametric studies away from the baseline values of the three-shaft and combined cycles
were performed to determine the effect of varying conditions in the cycle.
Recommendations on the optimal working fluid for each configuration were made.
The helium working fluid produced the highest overall plant efficiency for the
three-shaft and reheat cycle; however, the nitrogen-helium mixture produced similar
efficiency with smaller component sizes. The CO2 working fluid is recommend in the
combined cycle configuration.
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Norris, Elizabeth L. "Steam reforming of methane over alumina supported nickel catalysts : influence of calcination temperature, gold doping and sulfur addition." Thesis, Keele University, 2013. http://eprints.keele.ac.uk/3817/.
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Alumina supported nickel and gold-doped nickel catalysts have been investigated for their use as hydrocarbon steam reforming catalysts. The influence of calcination temperature during preparation has been investigated using a variety of techniques including X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), BET surface area analysis, scanning electron microscopy (SEM) and temperature-programmed reduction (TPR). It has been shown that the nickel phases present and their subsequent reducibility are strongly dependent upon the calcination temperature during preparation. As the calcination temperature is increased nickel aluminate (NiAl2O4) is formed and nickel oxide–support interactions increase. The addition of gold to the catalyst increases nickel oxide–support interactions, lowering the sample reducibility and increasing formation of NiAl2O4 at lower calcination temperatures. The calcination temperature significantly influences the steam methane reforming characteristics under both stoichiometric and methane-rich reaction conditions and the presence of unreduced NiAl2O4 significantly alters catalytic activity. Under the reaction conditions employed, the presence of gold provides no long-term benefit towards catalyst performance, resulting in a reduced reforming activity, especially at lower reaction temperatures, and in certain cases an increase in carbon laydown. Sulfur addition to the reaction mixture results in catalyst poisoning and in some cases complete deactivation, particularly at low reaction temperatures. However, sulfur addition does significantly increase resistance to carbon deposition. The addition of sulfur to the reaction mixtures and gold-doping of catalysts provides an increase in carbon resistance, whilst significantly reducing the rate of sulfur poisoning and increasing catalyst lifetime. This research discusses the influence of calcination temperature on steam methane reforming activity, catalyst resistance towards carbon formation and sulfur tolerance under variable reforming conditions over alumina supported nickel and gold-doped alumina supported nickel catalysts.
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Omojola, Kayode. "High temperature co-electrolysis of carbon dioxide and steam in a solid oxide cell for synthesis gas production." Thesis, University of Sheffield, 2015. http://etheses.whiterose.ac.uk/8497/.
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The utilisation of CO2 as a feedstock in the production of valuable products such as synthetic fuel is a promising pathway for mitigating its atmospheric concentration. A review of the high temperature co-electrolysis of CO2 and H2O in a solid oxide cell for syngas production has identified that further understanding of the co-electrolysis reaction mechanism is one of three key areas of development. In this work, a co-electrolysis test facility was designed, developed and commissioned. Additionally, the performance of a NextCellTM electrolyte supported cell was investigated for CO2 electrolysis and CO2/H2O co-electrolysis with an aim to gain a better understanding of the reaction mechanism. During CO2 electrolysis, an increase in cell area specific resistance was observed with increasing CO2 concentration. In addition, AC impedance spectra measurements showed a significant increase in polarisation resistance at the fuel electrode with increasing CO2/CO ratio. Short term durability studies carried out at -0.5 A/cm2, 850oC and fuel electrode compositions of 50% CO2, 25% CO and 25% N2 showed a sharp increase in cell voltage corresponding to a passivation rate of 120 mV/h in the first 5 hours of operation. This increase in cell voltage was caused by the adsorption of impurities to the Ni surface prompting partial blockage of the active Ni sites. During CO2/H2O co-electrolysis, the exhaust gas compositions measured at open circuit voltage were ±2 mol % of the thermodynamic equilibrium compositions. AC impedance spectra measurements showed a slight increase in polarisation resistance at the fuel electrode with increasing CO2/H2O concentration. Direct current measurements showed a 21% increase in cell performance during CO2/H2O co-electrolysis compared to CO2 electrolysis. Furthermore, co-electrolysis durability studies carried out at -0.5 A/cm2 showed a significantly lower degradation rate of 1.3 mV/h over 44 hours of operation compared to CO2 electrolysis.
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Sugihara, Shinichi. "Experimental Study of a Direct Internal Reforming Solid Oxide Fuel Cell：Thermal Effects of Steam-Methane Reforming Reactions." Kyoto University, 2020. http://hdl.handle.net/2433/259041.
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Li, Han. "Statistical Modeling and Analysis of Bivariate Spatial-Temporal Data with the Application to Stream Temperature Study." Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/70862.
Full textAbstract:
Water temperature is a critical factor for the quality and biological condition of streams. Among various factors affecting stream water temperature, air temperature is one of the most important factors related to water temperature. To appropriately quantify the relationship between water and air temperatures over a large geographic region, it is important to accommodate the spatial and temporal information of the steam temperature. In this dissertation, I devote
effort to several statistical modeling techniques for analyzing bivariate spatial-temporal data in a stream temperature study.
In the first part, I focus our analysis on the individual stream. A time varying coefficient model (VCM) is used to study the relationship between air temperature and water temperature for each stream. The time varying coefficient model enables dynamic modeling of the relationship, and therefore can be used to enhance the understanding of water and air temperature relationships. The proposed model is applied to 10 streams in Maryland, West Virginia, Virginia, North Carolina and Georgia using daily maximum temperatures. The VCM approach increases the prediction accuracy by more than 50% compared to the simple linear regression model and the nonlinear logistic model.
The VCM that describes the relationship between water and air temperatures for each stream is represented by slope and intercept curves from the fitted model. In the second part, I consider water and air temperatures for different streams that are spatial correlated. I focus on clustering multiple streams by using intercept and slope curves estimated from the VCM. Spatial information is incorporated to make clustering results geographically meaningful. I further propose a weighted distance as a dissimilarity measure for streams, which provides a flexible framework to interpret the clustering results under different weights. Real data analysis shows that streams in same cluster share similar geographic features such as solar radiation, percent forest and elevation.
In the third part, I develop a spatial-temporal VCM (STVCM) to deal with missing data. The STVCM takes both spatial and temporal variation of water temperature into account. I develop a novel estimation method that emphasizes the time effect and treats the space effect as a varying coefficient for the time effect. A simulation study shows that the performance of the STVCM on missing data imputation is better than several existing methods such as the neural network and the Gaussian process. The STVCM is also applied to all 156 streams in this study to obtain a complete data record.Ph. D.
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Saunders, James Edward Appleby. "The development of optical measurement techniques for gas species and surface temperature on a planar SOFC methane-steam reformer." Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/33380.
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This thesis presents the development of an experimental apparatus and methods to allow the application of gaseous Raman spectroscopy to the challenging and original application of a small-scale, high-temperature methane/steam reformer developed to be representative of the technologies used in solid oxide fuel cell (SOFC) applications. The research is placed in the context of global energy trends and SOFC’s, with specific reference to the challenges related to directly internally reforming medium-temperature SOFC’s and the case for the development of non-intrusive measurement techniques for gas species and temperature is made. The practical aspects of the development of the broadband 308 nm Raman system are examined and previous works in this area are highlighted. The excitation light source is evaluated, the use of a liquid potassium hydrogen phthalate filter as a means to reduce Rayleigh line effects is demonstrated, and background fluorescence suppression through polarization of the 308 nm light source is presented. The arrangements of the experimental set-up, gas supply, metering, and humidification are shown, as are the optical arrangements for laser sheet formation and light collection. A description of the calibration experiments, procedures, and methodologies that are used to define the normalised relative differential Raman scattering cross sections of the major species of interest in this study is presented. The observation of an unexpected leakage of air into the reformer is described and a hypothesis is presented to explain the ingress of air. Finally, results are presented that describe the response of the optically-accessed reformer to variations in; operating temperature, humidification factor, total volume flow rate, methane volume flow rate, and the methane residency time within the reformer channel. From these results it was possible to conclude that increased reformer temperature increased reaction rate, increased gas residency time in the channel increased hydrogen production, and reactant streams with higher inlet mole fractions of methane resulting in increased reaction rates and amounts of hydrogen production. The performance of the reformer rig and the suitability of optical diagnostic techniques to the application of a SOFC scale reformer are discussed.
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Lundqvist, Mårten. "A techno-economic analysis of implementing temperature-maintaining modifications on the steam turbine of a solar thermal power plant." Thesis, KTH, Energiteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-201652.
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This master thesis examines the techno-economic implications of introducing temperature maintaining modifications on the steam turbine in a direct steam generation solar tower power plant. More specifically, the impact on the maintenance requirements and other performance indicators when installing electrical heat blankets as well as increasing the gland steam temperature, was examined. A model of the Ivanpah plant in southern California was inherited and further developed within the KTH in-house tool DYESOPT to then be used for sensitivity studies focusing on examining the effect of the start improvements.The results show that with the assumptions made, the examined start improvements can be used to significantly increase the power output of the Ivanpah plant while at the same time reducing the maintenance requirements. The investment costs of said improvements were also found to be low in relation to their techno-economic benefits, resulting in a significant reduction of the levelized cost of electricity. The conducted sensitivity studies also suggested that the assumption made were not very sensitive, although more accurate assumptions regarding the costs of the turbine start improvements should be looked at during further development.Detta examensarbete undersöker de tekniska och ekonomiska konsekvenserna av att implementera turbinmodifikationer i syfte att undvika värmeförluster på ett termiskt solkraftverk. Mer specifikt så studerades det hur elektiska värmefiltar samt en ökning av temperaturen på förseglingsångan påverkar ett kraftverkets underhållsbehov samt andra prestationsindikatorer. För att åstadkomma detta ärvdes samt utvecklades en existerande modell av Ivanpah, ett solkraftverk beläget i Kalifornien, USA i KTHs egenutvecklade modelleringsverktyg DYESOPT. Detta verktyg användes sedan i syfte att undersöka effekten av turbinmodifikationerna genom en känslighetsanalys.Resultaten visar att med de antaganden som gjorts så kan de undersökta turbinmodifikationerna öka den årliga kraftproduktionen och samtidigt sänka underhållsbehoven betydligt. Sett till de ekonomiska aspekterna leder detta till en minskning av den sammanlagda kostnaden för att generera elektricitet med de antaganden som gjorts, eftersom investeringskostnaderna relaterade till modifikationerna är låga i relation till deras fördelar. Känslighetsanalysen pekar dessutom på att de gjorda antagandena inte var särskilt känsliga, men att fokus bör ligga på bättre underbyggda antaganden kring turbinmodifikationernas kostnader för att kunna bedöma dess tekno-ekonomiska effekter än bättre.
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Zanzi, Rolando. "Pyrolysis of biomass. Rapid pyrolysis at high temperature. Slow pyrolysis for active carbon preparation." Doctoral thesis, KTH, Chemical Engineering and Technology, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3180.
Full textAbstract:
Pyrolysis of biomass consists of heating solid biomass inthe absence of air to produce solid, liquid and gaseous fuels.In the first part of this thesis rapid pyrolysis of wood(birch) and some agricultural residues (olive waste, sugarcanebagasse and wheat straw in untreated and in pelletized form) athigh temperature (800ºC1000ºC) is studied ina free fall reactor at pilot scale. These conditions are ofinterest for gasification in fluidized beds. Of main interestare the gas and char yields and compositions as well as thereactivity of the produced char in gasification.
A higher temperature and smaller particles increase theheating rate resulting in a decreased char yield. The crackingof the hydrocarbons with an increase of the hydrogen content inthe gaseous product is favoured by a higher temperature and byusing smaller particles. Wood gives more volatiles and lesschar than straw and olive waste. The higher ash content inagricultural residues favours the charring reactions. Charsfrom olive waste and straw are more reactive in gasificationthan chars from birch because of the higher ash content. Thecomposition of the biomass influences the product distribution.Birch and bagasse give more volatiles and less char thanquebracho, straw and olive waste. Longer residence time inrapid pyrolysis increase the time for contact between tar andchar which makes the char less reactive. The secondary charproduced from tar not only covers the primary char but alsoprobably encapsulates the ash and hinders the catalytic effectof the ash. High char reactivity is favoured by conditionswherethe volatiles are rapidly removed from the particle, i.e.high heating rate, high temperature and small particles.
The second part of this thesis deals with slow pyrolysis inpresence of steam for preparation of active carbon. Theinfluence of the type of biomass, the type of reactor and thetreatment conditions, mainly temperature and activation time,on the properties and the yield of active carbons are studied.The precursors used in the experiments are birch (wood) anddifferent types of agricultural residues such as sugarcanebagasse, olive waste, miscanthus pellets and straw in untreatedand pelletized form.
The results from the pyrolysis of biomass in presence ofsteam are compared with those obtained in inert atmosphere ofnitrogen. The steam contributes to the formation of solidresidues with high surface area and good adsorption capacity.The yield of liquid products increases significantly at theexpense of the gaseous and solid products. Large amount ofsteam result in liquid products consisting predominantly ofwater-soluble polar compounds.
In comparison to the stationary fixed bed reactor, therotary reactor increases the production of energy-rich gases atthe expense of liquid products.
The raw materials have strong effect on the yields and theproperties of the pyrolysis products. At equal time oftreatment an increase of the temperature results in a decreaseof the yield of solid residue and improvement of the adsorptioncapacity until the highest surface area is reached. Furtherincrease of the temperature decreases the yield of solidproduct without any improvement in the adsorption capacity. Therate of steam flow influences the product distribution. Theyield of liquid products increases while the gas yielddecreases when the steam flow is increased.
Keywords: rapid pyrolysis, pyrolysis, wood, agriculturalresidues,biomass, char, tar, gas, char reactivity,gasification, steam, active carbon
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Nigbur, Corbinian [Verfasser], and Jörg [Akademischer Betreuer] Starflinger. "Advanced modelling of the high-temperature oxidation of zirconium in steam exploiting self-consistent thermodynamic data / Corbinian Nigbur ; Betreuer: Jörg Starflinger." Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2020. http://d-nb.info/1227927851/34.
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Kent, Logan. "The effects of salinity and temperature on toxicity of permethrin to pyrethroid-resistant and Wild-type Hyalella azteca." OpenSIUC, 2021. https://opensiuc.lib.siu.edu/theses/2894.
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Global climate change promotes warming temperatures and altered salinities that pose threats to aquatic ecosystems and species, such as Hyalella azteca. Moreover, these threats to aquatic ecosystems are exacerbated by agricultural, urban, and industrial pesticide runoff. In the state of California in 2012, pyrethroid insecticides were the seventh most applied group by licensed professional applicators for pest control and landscape maintenance. Some species, specifically H. azteca have developed non-target resistance to pyrethroids in California. It is imperative to understand whether the bioenergetic cost of resistance makes H. azteca more susceptible to warming and salinity effects in the presence of contaminants. This research presents an assessment on how multiple stressors can affect the toxicity of permethrin (pyrethroid insecticide) on one Wild-type and two pyrethroid- resistant species of H. azteca, belonging to different clades. A series of 96-h acute toxicity tests exposing animals to a concentration range of permethrin were performed with compounding stress from temperatures (18, 23 and 28 °C) and salinities (0.2, 1.0, and 6.0 practical salinity units [PSU]). Findings indicate resistant H. azteca cultured in pyrethroid-free settings have maintained resistance to permethrin over time, whereas the wild-type population did not develop any resistance over the course of experimentation. For resistant H. azteca, changes in salinity and temperature both increased and decreased survival of H. azteca exposed to permethrin. Between the two resistant clades, not only was survival affected, but the average slope of the dose-response curve was significantly different (p < 0.05); clade D was more susceptible to pyrethroids when coping with warming and higher salinity than clade C., Differential susceptibility potentially indicates that distinct resistance mutations confer a difference in the potency and mode of toxic action. The results provide insight to how changes posed by climate change, coupled with pyrethroid pesticides could be detrimental to this species, and conversely, how in some scenarios, changes to temperature and salinity might actually benefit the survival of H. azteca. These findings further indicate the importance of considering global climate change effects into risk assessments of emerging and legacy use contaminants.
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Alipour, Yousef. "High temperature corrosion in a biomass-fired power boiler : Reducing furnace wall corrosion in a waste wood-fired power plant with advanced steam data." Licentiate thesis, KTH, Yt- och korrosionsvetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-121155.
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The use of waste (or recycled) wood as a fuel in heat and power stations is becoming more widespread in Sweden (and Europe), because it is CO2 neutral with a lower cost than forest fuel. However, it is a heterogeneous fuel with a high amount of chlorine, alkali and heavy metals which causes more corrosion than fossil fuels or forest fuel. A part of the boiler which is subjected to a high corrosion risk is the furnace wall (or waterwall) which is formed of tubes welded together. Waterwalls are made of ferritic low-alloyed steels, due to their low price, low stress corrosion cracking risk, high heat transfer properties and low thermal expansion. However, ferritic low alloy steels corrode quickly when burning waste wood in a low NOx environment (i.e. an environment with low oxygen levels to limit the formation of NOx). Apart from pure oxidation two important forms of corrosion mechanisms are thought to occur in waste environments: chlorine corrosion and alkali corrosion. Although there is a great interest from plant owners to reduce the costs associated with furnace wall corrosion very little has been reported on wall corrosion in biomass boilers. Also corrosion mechanisms on furnace walls are usually investigated in laboratories, where interpretation of the results is easier. In power plants the interpretation is more complicated. Difficulties in the study of corrosion mechanisms are caused by several factors such as deposit composition, flue gas flow, boiler design, combustion characteristics and flue gas composition. Therefore, the corrosion varies from plant to plant and the laboratory experiments should be complemented with field tests. The present project may thus contribute to fill the power plant corrosion research gap. In this work, different kinds of samples (wall deposits, test panel tubes and corrosion probes) from Vattenfall’s Heat and Power plant in Nyköping were analysed. Coated and uncoated samples with different alloys and different times of exposure were studied by scanning electron microscopy (SEM), energy dispersive x-ray analysis (EDX), X-ray diffraction (XRD) and light optical microscopy (LOM). The corrosive environment was also simulated by Thermo-Calc software. The results showed that a nickel alloy coating can dramatically reduce the corrosion rate. The corrosion rate of the low alloy steel tubes, steel 16Mo3, was linear and the oxide scale non-protective, but the corrosion rate of the nickel-based alloy was probably parabolic and the oxide much more protective. The nickel alloy and stainless steels showed good corrosion protection behavior in the boiler. This indicates that stainless steels could be a good (and less expensive) alternative to nickel-based alloys for protecting furnace walls. The nickel alloy coated tubes (and probe samples) were attacked by a potassium-lead combination leading to the formation of non-protective potassium lead chromate. The low alloy steel tubes corroded by chloride attack. Stainless steels were attacked by a combination of chlorides and potassium-lead. The Thermo-Calc modelling showed chlorine gas exists at extremely low levels (less than 0.1 ppm) at the tube surface; instead the hydrated form is thermodynamically favoured, i.e. gaseous hydrogen chloride. Consequently chlorine can attack low alloy steels by gaseous hydrogen chloride rather than chlorine gas as previously proposed. This is a smaller molecule than chlorine which could easily diffuse through a defect oxide of the type formed on the steel.QC 20130423
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Neagu, Dragos. "Materials and microstructures for high temperature electrochemical devices through control of perovskite defect chemistry." Thesis, University of St Andrews, 2013. http://hdl.handle.net/10023/3606.
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The development of technologies that enable efficient and reliable energy inter-conversion and storage is of key importance for tempering the intermittent availability of renewable energy sources, and thus for developing an energy economy based on sustainable, clean energy production. Solid oxide electrolysis cells (SOECs) may be used to store excess electrical energy as hydrogen, while solid oxide fuel cells (SOFCs) could convert back hydrogen into electricity, thus balancing energy availability and demand. However, the current state-of-the-art hydrogen electrode used in both SOECs and SOFCs, the Ni-yttria-stabilised zirconia cermet (Ni-YSZ), is unreliable in conjunction with intermittent energy sources, in particular due to its innate redox instability. This thesis explores the fundamental properties of various inherently redox stable A-site deficient titanate perovskite systems (A1-αBO3, B = Ti), seeking to uncover the principles that enhance their properties so that they may be used to replace Ni-YSZ. In particular, this work demonstrates that the versatility of perovskites with respect to the introduction of lattice defects such as vacancies and cation substitutions enables considerable improvements in the extent of reduction, electronic conductivity and overall electrochemical activity. Most importantly, the defect chemistry context set by the presence of A-site vacancies was found to trigger the exsolution of electrocatalytically active nanoparticles from the parent perovskite, upon reduction. This is an entirely new phenomenon which was explored and exploited throughout this study to produce perovskite surfaces decorated with uniformly distributed catalytically active nanoparticles. As demonstrated in this study, the exsolution phenomenon excels in terms of producing nanoparticles with uniform size, distribution, diverse composition and ‘unconventional' surface anchorage. The resulting enhanced properties, and especially the exsolution phenomenon, contributed coherently towards improving the suitability of the perovskites developed here towards their application as hydrogen electrode materials. Consequently, when integrated into SOEC button cells as hydrogen electrodes, they exhibited a step-change increase in performance compared to other perovskites considered to date. Many of the principles and perovskite defect chemistry explored and exemplified in this study on perovskite titanates may be extended to other perovskites as well. In particular the advanced control and understanding achieved in this work over the exsolution phenomenon may inspire the formulation of new and sophisticated oxide materials with advanced functionality.
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Yue, Xiangling. "The development of alternative cathodes for high temperature solid oxide electrolysis cells." Thesis, University of St Andrews, 2013. http://hdl.handle.net/10023/6531.
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This study mainly explores the development of alternative cathode materials for the electrochemical reduction of CO₂ by high temperature solid oxide electrolysis cells (HTSOECs), which operate in the reverse manner of solid oxide fuel cells (SOFCs). The conventional Ni-yttria stabilized zirconia (YSZ) cermets cathode suffered from coke formation, whereas the perovskite-type (La, Sr)(Cr, Mn)O₃ (LSCM) oxide material displayed excellent carbon resistance. Initial CO₂ electrolysis performance tests from different cathode materials prepared by screen-printing showed that LSCM based cathode performed poorer than Ni-YSZ cermets, due to non-optimized microstructure. Efforts were made on microstructure modification of LSCM based cathodes by means of various fabrication methods. Among the LSCM/YSZ graded cathode, extra catalyst (including Pd, Ni, CeO₂, and Pt) aided LSCM/GDC (Gd₀.₁Ce₀.₉O₁.₉₅) cathode, LSCM impregnated YSZ cathode, and GDC impregnated LSCM cathode, the GDC impregnated LSCM cathode, with porous LSCM as backbone for finely dispersed GDC nanoparticles, was found to possess the desired microstructure for CO₂ splitting reaction via SOEC. Incorporating of 0.5wt% Pd into GDC impregnated LSCM cathode gave rise to an Rp of 0.24 Ω cm² at open circuit voltage (OCV) at 900°C in CO₂-CO 70-30 mixture, comparable with the Ni/YSZ cermet cathode operated in the identical conditions. Meanwhile, the cathode kinetics and possible mechanisms of the electrochemical reduction of CO₂ were studied, and factors including CO₂/CO composition, operation temperature and potential were taken into account. The current-to-chemical efficiency of CO₂ electrolysis was evaluated with gas chromatography (GC). The high performance Pd and GDC co-impregnated LSCM cathode was also applied for CO₂ electrolysis without protective CO gas in feed. This cathode also displayed superb performance towards CO₂ electrochemical reduction under SOEC operation condition in CO₂/N₂ mixtures, though it had OCV as low as 0.12V at 900°C. The LSCM/GDC set of SOEC cathode materials were investigated in the application of steam electrolysis and H₂O-CO₂ co-electrolysis as well. For the former, adequate supply of steam was essential to avoid the appearance of S-shaped I-V curves and limited steam transport. The 0.5wt% Pd and GDC co-infiltrated LSCM material has been found to be a versatile cathode with high performance and good durability in SOEC operations.
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Křivánek, Robin. "Navrhněte parní kotel na spalování zemního plynu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2014. http://www.nusl.cz/ntk/nusl-231250.
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This diploma thesis describes the design of steam boiler for combustion natural gas, which has a steam power 80t/hour. In the first phase is performed calculation of stoichiometric amount of combustion air and flue gas. After that follows constructional proposal of the combustion chamber. Furthermore continue by calculation heating surfaces of the boiler. In conclusion, the thesis is focused on designing the injections. To check the accuracy of the results is recalculated heat balance the whole boiler.