The Experts below are selected from a list of 1107 Experts worldwide ranked by ideXlab platform
Chuguang Zheng - One of the best experts on this subject based on the ideXlab platform.
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mercury adsorption and oxidation over magnetic biochar in Oxyfuel Combustion atmosphere impact of enriched co2 and h2o
Fuel, 2019Co-Authors: Yuming Zhou, Junying Zhang, Yongchun Zhao, Chuguang ZhengAbstract:Abstract The abatement of mercury from Oxyfuel Combustion flue gas should be paid special attention due to the metal embrittlement and aluminum corrosion for CO2 compression device. The effects of enriched CO2 and H2O in Oxyfuel Combustion atmosphere on mercury removal over biochar (BC) and magnetic biochar (MBC) was studied. Hg0 was firstly captured by physical adsorption and then oxidized to various mercury compounds. A large amount of organic groups, especially C O group, were formed with the assistance of enriched CO2. As a result, more Hg0 was oxidized over BC and more organic Hg (Hg-OM) was formed on BC and MBC. However, the content of chemisorbed oxygen on MBC was reduced under Oxyfuel Combustion atmosphere, hence reducing the formation of HgO on MBC compared with air Combustion atmosphere. The enriched H2O significantly inhibited the removal of mercury over MBC. Chlorine was demonstrated as the most significant active components for mercury removal, since HgCl2 was the dominant species on MBC. This work clarified the effects of enriched CO2 and H2O on Hg0 adsorption over BC and MBC, which is essential for further improving the adsorption activity.
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mercury emission and speciation in fly ash from a 35 mwth large pilot boiler of Oxyfuel Combustion with different flue gas recycle
Fuel, 2017Co-Authors: Jianping Yang, Jun Xiang, Shihong Zhang, Yongchun Zhao, Junying Zhang, Yi Zhang, Yongxin Feng, Kai Xu, Chuguang ZhengAbstract:Abstract The behaviour of mercury is investigated in a 35 MW th large pilot boiler of Oxyfuel Combustion with dry and wet flue gas recycle (FGR). The mercury species in fly ash particles as well as the involved reaction mechanism are systematically investigated. The results suggest that higher concentration of gas–phase mercury (Hg g ) is contained in Oxyfuel Combustion flue gas. The conversion of Hg g to particulate associated mercury (Hg p ) is enhanced in Oxyfuel Combustion. Different mercury species are presented in fly ash collected from air and Oxyfuel Combustion: trigonal red HgS is the main mercury species in air Combustion; mercury bound to organic matter (Hg–OM) and trigonal red HgS are both dominant in the samples from Oxyfuel Combustion. The prominent difference is the significantly increase of Hg–OM in Oxyfuel Combustion atmosphere. The Oxyfuel Combustion atmosphere would favor the formation of oxygen–rich functional groups, especially the C O group, which is responsible for the adsorption of mercury and formation of Hg–OM in fly ash.
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methane Combustion in mild Oxyfuel regime influences of dilution atmosphere in co flow configuration
Energy, 2017Co-Authors: Sheng Chen, Chuguang ZhengAbstract:MILD (moderate or intense low oxygen dilution) Oxyfuel Combustion is a recently proposed clean Combustion mode which can remedy the shortcomings of the standard Oxyfuel Combustion technology. Nowadays most available studies on MILD Oxyfuel Combustion focus on how to realize this new Combustion regime in O2/CO2 atmosphere. The open research on methane MILD Oxyfuel Combustion in O2/H2O atmosphere is quite sparse. In the present work, we carry out a comprehensive comparison study on methane MILD Oxyfuel Combustion in different dilution atmosphere for the first time. The JHC (jet in hot co-flow) burner is adopted as a research prototype. The investigation is based on numerical simulation, so firstly the adopted numerical approach is validated by some experimental data in open literature. The numerical comparison is conducted by varying the mass fraction of oxygen in the co-flow and the temperature of the hot co-flow, two key parameters affecting fine reaction structures in JHC. Through the present investigation, a number of findings are reported for the first time and some conclusions presented in previous publications are checked with analyses, especially on some conflicted claims between the previous publications. In addition, several new questions are raised, which may inspire further research activities in future.
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A numerical investigation on flame stability of oxy-coal Combustion: Effects of blockage ratio, swirl number, recycle ratio and partial pressure ratio of oxygen
International Journal of Greenhouse Gas Control, 2017Co-Authors: Sheng Chen, Stanley Santos, Chuguang ZhengAbstract:Abstract Keeping the flame stable and having the appropriate flame shape is essential in operating an Oxyfuel Combustion coal fired power plant with CO 2 capture. This is more critical if the boiler is required to operate in full and partial thermal load with varying volume of flue gas recycled. Therefore, in designing the Oxyfuel Combustion burner, it is important to evaluate the burner stability, shape structure and flame type. This work presents numerical investigation of a burner designed for Oxyfuel Combustion coal fired boiler. The study evaluated the effects of the blockage ratio, swirl number, flue gas recycle ratio, and oxygen partial pressure in the primary RFG stream on the flame stability, type, shape and structure. The model results were validated against experimental data obtained from a novel Oxyfuel Combustion burner designed and operated in a 2.5MWt test pilot facility. The model developed for this study incorporated a modified chemical reaction mechanism that allows the addition of CO and Boudouard reaction that is considered significant in an Oxyfuel Combustion flame. The results show that the stability of an Oxyfuel Combustion flame is greatly improved by having a moderate to strong internal recirculation zone to produce a Type-II flame; and could also be easily destabilized by a high velocity jet of unburned carbon/char as illustrated by a dark central region emanating from the centre of the burner. Additionally, it could also be illustrated that the swirl number and flue gas recycle ratio have a strong influence to the formation of the central dark region along the centerline of the burner. It could be concluded that maintaining the flame Type-II over the whole range of thermal load should maintain the necessary flame stability appropriate to an Oxyfuel Combustion boiler.
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methane Combustion in various regimes first and second thermodynamic law comparison between air firing and Oxyfuel condition
Energy, 2016Co-Authors: Kai Xu, Yongxin Feng, Sheng Chen, Chuguang ZhengAbstract:MILD Oxyfuel Combustion has been attracting increasing attention as a promising clean Combustion technology. How to design a pathway to reach MILD Oxyfuel Combustion regime and what can provide a theoretical guide to design such a pathway are two critical questions that need to be answered. So far there has been no open literature on these issues. A type of Combustion regime classification map proposed in our previous work, based on the so-called ”Hot Diluted Diffusion Ignition” (HDDI) configuration, is adopted here as a simple but useful tool to solve these problems. Firstly, we analyze comprehensively the influences of various dilution atmosphere and fuel type on Combustion regimes. The Combustion regime classification maps are made out according to the analyses. In succession, we conduct a comparison between the map in air-firing condition and its Oxyfuel counterpart. With the aid of the second thermodynamic-law analysis on the maps, it is easy to identify the major contributors to entropy generation in various Combustion regimes in advance, which is crucial for Combustion system optimization. Moreover, we find that, for the first time, a Combustion regime classification map also may be used as a safety indicator. With the aid of these maps, some conclusions in previous publications can be explained more straightforwardly.
Christian Bergins - One of the best experts on this subject based on the ideXlab platform.
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First test results of Oxyfuel Combustion with Hitachi’s DST-burner at Vattenfall’s 30 MWth Pilot Plant at Schwarze Pumpe
Energy Procedia, 2011Co-Authors: Sebastian Rehfeldt, Christian Kuhr, Franz-peter Schiffer, Patrick Weckes, Christian BerginsAbstract:Abstract Situated in the near of Schwarze Pumpe power station southeast of Berlin, Germany, Vattenfall operates a 30 MWth pilot plant in order to investigate the Oxyfuel process. Hitachi Power Europe delivered a DST-burner (DST-Brenner ® ) for the indirect firing system of the plant which was installed without modifications to the pressure part of the boiler. The Combustion behavior during Oxyfuel operation was investigated and optimal burner settings for different operation points were established. The results show that the burner can be operated in a wide range of oxygen concentrations in the oxidant gas flow. The burner is characterized by low emissions of carbon monoxide and nitrogen oxides. The high flame stability was found to be unaffected by operational influences such as fluctuations in the coal mass flow, coal quality or soot blowing. Due to the high flame stability the change-over from air blown to Oxyfuel Combustion can be realized very easily and is automated. During Oxyfuel operation measurements of temperatures and flue gas species in the flame were performed. The measurement values were compared with the values of the Combustion modeling by computational fluid dynamics. The good agreement between both measurement and modeling shows the suitability of the applied models to predict the Combustion behavior under Oxyfuel conditions.
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first test results of Oxyfuel Combustion with hitachi s dst burner at vattenfall s 30 mwth pilot plant at schwarze pumpe
Energy Procedia, 2011Co-Authors: Sebastian Rehfeldt, Christian Kuhr, Franz-peter Schiffer, Patrick Weckes, Christian BerginsAbstract:Abstract Situated in the near of Schwarze Pumpe power station southeast of Berlin, Germany, Vattenfall operates a 30 MWth pilot plant in order to investigate the Oxyfuel process. Hitachi Power Europe delivered a DST-burner (DST-Brenner ® ) for the indirect firing system of the plant which was installed without modifications to the pressure part of the boiler. The Combustion behavior during Oxyfuel operation was investigated and optimal burner settings for different operation points were established. The results show that the burner can be operated in a wide range of oxygen concentrations in the oxidant gas flow. The burner is characterized by low emissions of carbon monoxide and nitrogen oxides. The high flame stability was found to be unaffected by operational influences such as fluctuations in the coal mass flow, coal quality or soot blowing. Due to the high flame stability the change-over from air blown to Oxyfuel Combustion can be realized very easily and is automated. During Oxyfuel operation measurements of temperatures and flue gas species in the flame were performed. The measurement values were compared with the values of the Combustion modeling by computational fluid dynamics. The good agreement between both measurement and modeling shows the suitability of the applied models to predict the Combustion behavior under Oxyfuel conditions.
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conversion of existing coal fired power plants to Oxyfuel Combustion case study with experimental results and cfd simulations
Energy Procedia, 2009Co-Authors: K D Tigges, Friedrich Klauke, Christian Bergins, K Busekrus, J Niesbach, Martin Ehmann, Christian Kuhr, F Hoffmeister, Bernd Vollmer, Thorsten BuddenbergAbstract:Abstract Oxyfuel Combustion is one of the promising technologies to enable CCS for new and existing coal-fired power plants. For retrofit applications, Oxyfuel is an attractive option because it does not have major impact on the boiler-turbine steam cycle. This paper presents a case study for retrofitting Oxyfuel Combustion technology in large state-of-the-art power plants that are originally commissioned and operated in air-fired mode. The overall process design for the modified power plant is outlined; necessary modifications of relevant components are explained. The paper also discusses results of experiments and numerical calculations on Combustion behavior in the furnace. Retrofit measures ensure that the power stations still can run under both air-fired and Oxyfuel-fired conditions if required by regulations/market conditions. This provides additional operational and commercial benefits for the operator of the plant and reduces the technical risk of implementing new components and processes not yet proven in the power sector.
Sascha Priesnitz - One of the best experts on this subject based on the ideXlab platform.
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flue gas desulphurization for hot recycle Oxyfuel Combustion experiences from the 30 mwth Oxyfuel pilot plant in schwarze pumpe
International Journal of Greenhouse Gas Control, 2011Co-Authors: Richard Faber, Felix Stark, Sascha PriesnitzAbstract:Abstract Significant differences exist in the flue gas composition in hot recycle Oxyfuel conditions as e.g. the high CO 2 partial pressure (>90 vol%, dry), the very high SO 2 concentration and the high water content (approx. 30 vol%). Therefore certain design and operation criteria have to be observed for the flue gas desulphurization with forced oxidation under Oxyfuel Combustion conditions. Several performance tests have been executed at the 30 MW th Oxyfuel pilot plant in Schwarze Pumpe to evaluate the main performance parameters and to assess the influence of the major operation parameters. The results show that there are no fundamental problems for the operation of the flue gas desulphurization unit under Oxyfuel Combustion conditions. High removal rates could be reached and no negative impact of the high CO 2 partial pressure was observed under the tested operating conditions. No major differences in the gypsum quality have been observed between air firing and Oxyfuel conditions.
Richard Faber - One of the best experts on this subject based on the ideXlab platform.
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flue gas desulphurization for hot recycle Oxyfuel Combustion experiences from the 30 mwth Oxyfuel pilot plant in schwarze pumpe
International Journal of Greenhouse Gas Control, 2011Co-Authors: Richard Faber, Felix Stark, Sascha PriesnitzAbstract:Abstract Significant differences exist in the flue gas composition in hot recycle Oxyfuel conditions as e.g. the high CO 2 partial pressure (>90 vol%, dry), the very high SO 2 concentration and the high water content (approx. 30 vol%). Therefore certain design and operation criteria have to be observed for the flue gas desulphurization with forced oxidation under Oxyfuel Combustion conditions. Several performance tests have been executed at the 30 MW th Oxyfuel pilot plant in Schwarze Pumpe to evaluate the main performance parameters and to assess the influence of the major operation parameters. The results show that there are no fundamental problems for the operation of the flue gas desulphurization unit under Oxyfuel Combustion conditions. High removal rates could be reached and no negative impact of the high CO 2 partial pressure was observed under the tested operating conditions. No major differences in the gypsum quality have been observed between air firing and Oxyfuel conditions.
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flue gas cleaning for co2 capture from coal fired Oxyfuel Combustion power generation
Energy Procedia, 2011Co-Authors: Marie Anheden, Richard Faber, Fredrik Starfelt, Robert Preusche, Holger Ecke, Nader Padban, Daniel Kosel, Norbert Jentsch, Goran LindgrenAbstract:Abstract Current progress in flue gas cleaning for CO 2 capture from Oxyfuel Combustion has been described based on conceptual development, fundamental understanding and practical tests at the Schwarze Pumpe Oxyfuel Pilot Plant (OxPP). Significant improvement in understanding the characteristics of SO x , NO x , particulate matters (PMs) and non-condensable gas components in flue gas cleaning processes provide a scientific basis for further developments of flue gas cleaning technologies. Testing results from pilot studies have proved that flue gas cleaning systems have reached the achievable performance and have also shown that there is generally no fundamental technical bottleneck for most of the flue gas cleaning technologies. Further developments should focus on comprehensive optimisation of the flue gas cleaning processes combined with boiler and downstream CO 2 compression processes. Changes in flue gas cleaning technologies may be excepted if more attractive gas cleaning processes could be successfully developed in the near future; for example, NO x removal and control technologies. The development of a monitoring approach for the mitigation of non-condensable gases is an important operational issue for largescale Oxyfuel Combustion plant.
Par Jonsson - One of the best experts on this subject based on the ideXlab platform.
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numerical study on the effect of lambda value oxygen fuel ratio on temperature distribution and efficiency of a flameless Oxyfuel Combustion system
Energies, 2017Co-Authors: Mersedeh Ghadamgahi, Patrik Olund, Nils A I Andersson, Par JonssonAbstract:The flameless Oxyfuel Combustion technology has been proven to be a promising new method to reduce the fuel consumption and pollutants in industrial applications [...]
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Numerical Study on the Effect of Lambda Value (Oxygen/Fuel Ratio) on Temperature Distribution and Efficiency of a Flameless Oxyfuel Combustion System
Energies, 2017Co-Authors: Mersedeh Ghadamgahi, Patrik Olund, Nils A I Andersson, Par JonssonAbstract:The flameless Oxyfuel Combustion technology has been proven to be a promising new method to reduce the fuel consumption and pollutants in industrial applications [...]
