The Experts below are selected from a list of 135801 Experts worldwide ranked by ideXlab platform
R. Agnihotri - One of the best experts on this subject based on the ideXlab platform.
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Pilot-scale demonstration of the OSCAR process for high-temperature multipollutant control of coal combustion flue gas, using carbonated fly ash and mesoporous calcium carbonate
Industrial & Engineering Chemistry Research, 2007Co-Authors: Himanshu Gupta, R. Agnihotri, Theodore J. Thomas, Ah-hyung Alissa Park, Raja A. Jadhav, Harold W. Walker, Linda K Weavers, Mahesh V Iyer, Puneet Gupta, Tarunjit S. ButaliaAbstract:A pilot-scale study of the Ohio State Carbonation Ash Reactivation (OSCAR) process was performed to demonstrate the reactivity of two novel calcium-based Sorbents toward sulfur and trace heavy metal (arsenic, selenium, and mercury) capture in the furnace Sorbent injection (FSI) mode on a 0.365 m3/s slipstream of a bituminous coal-fired stoker boiler. The Sorbents were synthesized by bubbling CO2 to precipitate calcium carbonate (a) from the unreacted calcium present in the lime spray dryer ash and (b) from calcium hydroxide slurry that contained a negatively charged dispersant. The heterogeneous reaction between these Sorbents and SO2 gas occurred under entrained flow conditions by injecting fine Sorbent powders into the flue gas slipstream. The reacted Sorbents were captured either in a hot cyclone (∼650 °C) or in the relatively cooler downstream baghouse (∼230 °C). The baghouse samples indicated ∼90% toward sulfation and captured arsenic, selenium and mercury to 800 ppmw, 175 ppmw and 3.6 ppmw, respecti...
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Kinetics and structural evolution of Sorbents at high temperatures. Final report, September 1, 1994--February 29, 1996
1996Co-Authors: A. Ghosh-dastidar, S Mahuli, R. AgnihotriAbstract:The focus of this project is on furnace Sorbent injection technology using dry calcium-based Sorbents for the flue gas desulfurization. The goal is to provide fundamental research kinetics and effects of Sorbent properties, aimed at improving SO{sub 2} removal and increasing Sorbent utilization in a cost-effective manner. The fifth year project work has been carried out in two phases: (1) modified Sorbent studies to understand the influence of Sorbent modifications (both physical and chemical) on reaction mechanisms, and (2) development of a comprehensive sulfation model to interpret and predict short-time simultaneous calcination, sulfation and sintering processes. This report discusses these two phases of research.
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SO{sub 2} and heavy metal capture by calcium-based Sorbents in a coal-fired boiler
1995Co-Authors: A. Ghosh-dastidar, S Mahuli, R. AgnihotriAbstract:Injection of dry, calcium-based Sorbents to the upper-furnace (high temperature) or economizer (medium temperature) region of a coal-fired boiler has been widely studied as a low-cost retrofittable technology. However, the current state of furnace Sorbent injection technique falls far short of achieving adequate SO{sub 2} control for utilities burning high sulfur coal. Sorbent utilization with the conventional hydroxide or carbonate Sorbents is less than optimum (25-32 %) with a Ca/S ratio of 2, which achieves a low SO{sub 2} removal of around 60-65 %. Addition of various promoters such as calcium lignosulfonate to the pure Sorbents has resulted in moderate success, but still does not meet the stringent SO{sub 2} emission standard. The main stumbling block to improve the Sorbent injection process has been lack of a comprehensive understanding of the ultrafast complex phenomena (calcination, sintering, sulfation) during high-temperature (800-1200{degrees}C) sulfur capture. In this work, an attempt has been made to explore the short-time (0-200 ms) phenomena of the sulfur capture process by obtaining time-resolved kinetic data for various pure and modified Sorbents. Preliminary investigation has shown that Forsby limestone has a very high Sorbent utilization compared to other conventional pure and modified Sorbents. An attempt has been made tomore » elucidate the reasons behind its superior performance in sulfur capture. Another part of this work has involved capture of selenium at both high and medium temperature ranges with calcium hydroxide. The results suggest that at medium-temperature window (400-650{degrees}C), calcium hydroxide captures substantial metal oxide by a chemical reaction.« less
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Kinetics and structural evolution of Sorbents at high temperatures. Final report, September 1, 1993--August 31, 1994
1995Co-Authors: A. Ghosh-dastidar, S Mahuli, R. AgnihotriAbstract:The focus of this project is on furnace Sorbent injection technology using dry, calcium-based Sorbents for flue gas desulfurization. The goal is to provide fundamental research kinetics and the effects of Sorbent properties, aimed at improving S0{sub 2} removal and increasing Sorbent utilization in a cost-effective fashion. The fourth year work has been carried out in three phases: (1) structural evolution of Sorbent, (2) modified Sorbent studies, and (3) development of mathematical model. The results, their interpretation, and discussions are the primary focus of this report.
Panagiotis G Smirniotis - One of the best experts on this subject based on the ideXlab platform.
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facile synthesis of flame spray pyrolysis derived magnesium oxide nanoparticles for co2 sorption effect of precursors morphology and structural properties
Industrial & Engineering Chemistry Research, 2018Co-Authors: Thirupathi Oningari, Siva Nagi Reddy Inturi, Vasilios I Manousiouthakis, Panagiotis G SmirniotisAbstract:A series of MgO aerosol nanoparticles were prepared by using a flame aerosol method and examined for the CO2 sorption at low-temperatures. Our XRD results suggest the formation of high purity magnesium oxide (MgO) phase. The CO2 sorption was determined at temperatures ranging from 60 to 275 °C using thermogravimetric (TGA) analysis, where the results indicate that the increased CO2 sorption we observed is associated with the improved pore volume and surface area of the Sorbent. The as-synthesized MgO-A Sorbent exhibited the best CO2 sorption capacity (66.0 mg CO2/g Sorbent) at 60 °C in comparison with all of the Sorbents tested. The CO2 uptake is predominantly controlled by the pore architecture as well as ultramicropores. The uptake characteristics of selected MgO Sorbents we synthesized are significantly higher than that of CaO based Sorbents at low temperatures.
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calcium oxide based Sorbents for capture of carbon dioxide at high temperatures
Industrial & Engineering Chemistry Research, 2006Co-Authors: Hong Lu, Ettireddy P Reddy, Panagiotis G SmirniotisAbstract:Calcium oxide is a promising Sorbent for the capture of carbon dioxide. In this work, CaO Sorbents were prepared using different precursors, including Ca(NO3)2·4H2O, CaO, Ca(OH)2, CaCO3, and Ca(CH3COO)2·H2O. Of these, the Sorbent prepared from calcium acetate (CaAc2−CaO) resulted in the best uptake characteristics for CO2. This Sorbent had a higher BET surface area and larger pore volume than the other Sorbents. According to SEM images, this Sorbent exhibits a “fluffy” structure, which probably contributes to its high surface area and large pore volume. This Sorbent also showed almost 100% carbonation, at temperatures between 550 and 800 °C. Moreover, the carbonation progressed dominantly during an initial short period. Under numerous carbonation/decarbonation cycles, the CaAc2−CaO Sorbent demonstrated the best reversibility, even in the presence of 10 vol % water vapor. During a 27-cycle operation, the Sorbent maintained fairly high conversion of 62 mol % at 700 °C. Pore size distribution measurements in...
Bo Feng - One of the best experts on this subject based on the ideXlab platform.
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effect of sulfation on co2 capture of cao based Sorbents during calcium looping cycle
Fuel, 2014Co-Authors: Ying Zheng, Bo FengAbstract:Calcium looping cycle is considered as one of the most promising post combustion CO2 capture technologies that can curb CO2 emissions from power plants fired with fossil fuel. However the presence of SO2 and steam in the flue gas leads to the sulfation of CaO-based Sorbents, and thus reduces the Sorbents’ capacity for CO2 capture. In this study, the effect of Sorbent sulfation during both carbonation and calcination stage on the cyclic CO2 capture performance was investigated. The results showed that the reaction time, SO2 concentrations and steam greatly influenced the capacity of CaO-based Sorbent. The sulfation degree of the Sorbent decreased with the reduction of carbonation and calcination time per cycle. High SO2 concentration present with steam led to a rapid loss in capacity of the Sorbent within a few cycles. Furthermore, the synthetic Sorbent derived from a sol–gel process had much higher cyclic CO2 capture capacities than natural limestone Sorbent whether in conditions without SO2 or with SO2 and steam. Microscopic images showed that after multiple cycles in the presence of SO2 and steam, the porous structure of the synthetic Sorbent could be retained while limestone experienced serious pore blockage and agglomeration of grains.
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effect of support material on carbonation and sulfation of synthetic cao based Sorbents in calcium looping cycle
Energy & Fuels, 2013Co-Authors: Ying Zheng, Ning Ding, Chuguang Zheng, Bo FengAbstract:Calcium looping cycle for post-combustion CO2 capture has gained increasing attention worldwide. However, CaO-based Sorbents derived from natural sources for calcium looping cycle experience rapid loss of capacity during high-temperature cyclic carbonation/calcination reactions. Synthesizing sintering-resistant CaO-based Sorbents by adding a support material has been extensively studied as an effective method of combating the problem. The support material in the synthetic Sorbents plays an important role in retaining the capacity, and various support materials have been tested in the literature. In practical reactors, sulfur is present and it has been reported that sulfation of Sorbents will also reduce the CO2 capture capacity. However, thus far, it is not clear whether/how support material would affect sulfation of Sorbents and, thus, CO2 capture. In this paper, four different support materials, such as Ca2MnO4, La2O 3, Ca12Al14O33, and MgO, were studied. The cyclic CO2 capture performance of the synthetic Sorbents made from CaO and the support materials were investigated in detail, in the presence of SO2 and steam. The results showed that a mass ratio of 20-25% support material would be optimum for synthesizing Sorbents with high cyclic CO2 capture capacity, and Ca12Al14O 33 and MgO seem to be more effective than Ca2MnO 4 and La2O3. The 80:20 wt % CaO/MgO synthetic Sorbent achieved the highest CO2 capture capacity under ideal conditions over 100 cycles. However, the CaO/MgO Sorbent had a strong affinity to SO2 capture during cyclic reactions, especially in the presence of steam. Under realistic conditions (i.e., both SO2 and steam are present during carbonation), the CaO/MgO Sorbent showed the highest cumulative SO2 capture capacity, whereas the CaO/Ca12Al 14O33 Sorbent obtained the highest CO2 capture capacity after 10 cycles. The smaller average crystallite size of MgO in the Sorbent was responsible for the strong SO2 affinity of the CaO/MgO Sorbent as well as its stable cyclic CO2 capture abilities under ideal conditions.
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Performance of Extruded Particles from Calcium Hydroxide and Cement for CO2 Capture
Energy & Fuels, 2011Co-Authors: Hui An, Bo FengAbstract:The reversible reaction of CaO with CO2 can be used for CO2 capture. However, two challenging problems, i.e., loss-in-capacity and high attrition rate for CaO-based Sorbents, must be solved before it can be practically applied. In this paper, Sorbents with various CaO contents were prepared from calcium hydroxide and cement using a screw extruder and the physical and chemical properties of the Sorbents were obtained. The mechanical properties of Sorbent particles were tested by friability and compression testers, and the sorption capacity and regenerability were measured in a thermogravimetric analyzer. It appears that the Sorbents occupied acceptable attrition resistance and good mechanical strength. In the meantime, the Sorbent particles showed higher CO2-capture capacities compared to pure CaO after 18 cycles, which was attributed to the stable phase of Ca12Al14O33 in the Sorbents. The Sorbent particles would be suitable for the calcium looping processes.
Ying Zheng - One of the best experts on this subject based on the ideXlab platform.
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macropore stabilized limestone Sorbents prepared by the simultaneous hydration impregnation method for high temperature co2 capture
Energy & Fuels, 2016Co-Authors: Yongqing Xu, Ying Zheng, Haoran Ding, Liqi ZhangAbstract:A novel cost-effective method was applied to modified calcium-based Sorbents for cyclic high-temperature CO2 capture. The Sorbents were derived from cheap limestone and sea salt, and the main processes of the preparation involved two simple steps: hydration of CaO and impregnation with sea salt in CaO. Results indicated that the simultaneous hydration–impregnation (SHI) method contributed to the formation of highly improved calcium-based Sorbents during cyclic calcination/carbonation reactions. After 40 cycles, the SHI limestone doped with 3.0 wt % sea salt achieved a CO2 capture capacity of 0.31 g of CO2/g of Sorbent, which was 126% higher than that of natural limestone. Moreover, the SHI limestone Sorbent contained numerous macropores after several cycles. Further investigation on microstructure changes of the Sorbents showed that the macropores were relatively stable during cyclic reactions, which can be attributed to the stable behavior of the Sorbent. In contrast, the natural limestone lost its micro...
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effect of sulfation on co2 capture of cao based Sorbents during calcium looping cycle
Fuel, 2014Co-Authors: Ying Zheng, Bo FengAbstract:Calcium looping cycle is considered as one of the most promising post combustion CO2 capture technologies that can curb CO2 emissions from power plants fired with fossil fuel. However the presence of SO2 and steam in the flue gas leads to the sulfation of CaO-based Sorbents, and thus reduces the Sorbents’ capacity for CO2 capture. In this study, the effect of Sorbent sulfation during both carbonation and calcination stage on the cyclic CO2 capture performance was investigated. The results showed that the reaction time, SO2 concentrations and steam greatly influenced the capacity of CaO-based Sorbent. The sulfation degree of the Sorbent decreased with the reduction of carbonation and calcination time per cycle. High SO2 concentration present with steam led to a rapid loss in capacity of the Sorbent within a few cycles. Furthermore, the synthetic Sorbent derived from a sol–gel process had much higher cyclic CO2 capture capacities than natural limestone Sorbent whether in conditions without SO2 or with SO2 and steam. Microscopic images showed that after multiple cycles in the presence of SO2 and steam, the porous structure of the synthetic Sorbent could be retained while limestone experienced serious pore blockage and agglomeration of grains.
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effect of support material on carbonation and sulfation of synthetic cao based Sorbents in calcium looping cycle
Energy & Fuels, 2013Co-Authors: Ying Zheng, Ning Ding, Chuguang Zheng, Bo FengAbstract:Calcium looping cycle for post-combustion CO2 capture has gained increasing attention worldwide. However, CaO-based Sorbents derived from natural sources for calcium looping cycle experience rapid loss of capacity during high-temperature cyclic carbonation/calcination reactions. Synthesizing sintering-resistant CaO-based Sorbents by adding a support material has been extensively studied as an effective method of combating the problem. The support material in the synthetic Sorbents plays an important role in retaining the capacity, and various support materials have been tested in the literature. In practical reactors, sulfur is present and it has been reported that sulfation of Sorbents will also reduce the CO2 capture capacity. However, thus far, it is not clear whether/how support material would affect sulfation of Sorbents and, thus, CO2 capture. In this paper, four different support materials, such as Ca2MnO4, La2O 3, Ca12Al14O33, and MgO, were studied. The cyclic CO2 capture performance of the synthetic Sorbents made from CaO and the support materials were investigated in detail, in the presence of SO2 and steam. The results showed that a mass ratio of 20-25% support material would be optimum for synthesizing Sorbents with high cyclic CO2 capture capacity, and Ca12Al14O 33 and MgO seem to be more effective than Ca2MnO 4 and La2O3. The 80:20 wt % CaO/MgO synthetic Sorbent achieved the highest CO2 capture capacity under ideal conditions over 100 cycles. However, the CaO/MgO Sorbent had a strong affinity to SO2 capture during cyclic reactions, especially in the presence of steam. Under realistic conditions (i.e., both SO2 and steam are present during carbonation), the CaO/MgO Sorbent showed the highest cumulative SO2 capture capacity, whereas the CaO/Ca12Al 14O33 Sorbent obtained the highest CO2 capture capacity after 10 cycles. The smaller average crystallite size of MgO in the Sorbent was responsible for the strong SO2 affinity of the CaO/MgO Sorbent as well as its stable cyclic CO2 capture abilities under ideal conditions.
Henry W. Pennline - One of the best experts on this subject based on the ideXlab platform.
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Sorbents for mercury removal from flue gas
2015Co-Authors: Evan J. Granite, Richard A. Hargis, Henry W. PennlineAbstract:A review of the various promoters and Sorbents examined for the removal of mercury from flue gas is presented. Commercial Sorbent processes are described along with the chemistry of the various Sorbent-mercury interactions. Novel Sorbents for removing mercury from flue gas are suggested. Since activated carbons are expensive, alternate Sorbents and/or improved activated carbons are needed. Because of their lower cost, Sorbent development work can focus on base metal oxides and halides. Additionally, the long-term sequestration of the mercury on the Sorbent needs to be addressed. Contacting methods between the flue gas and the Sorbent also merit investigation.
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performance of immobilized tertiary amine solid Sorbents for the capture of carbon dioxide
International Journal of Greenhouse Gas Control, 2008Co-Authors: Mcmahan L. Gray, K. J. Champagne, John P. Baltrus, Daniel J Fauth, Henry W. PennlineAbstract:The capture of carbon dioxide (CO2) from a simulated flue gas stream was achieved by utilizing immobilized tertiary amine solid Sorbents. The tertiary amine immobilized in these solid substrates was 1, 8 Diazabicyclo-[5.4.0]-undec-7-ene (DBU) and it has the stoichiometric capability of capturing carbon dioxide at a 1:1 R-NH2:CO2 molar ratio. This is a unique feature compared to other primary and secondary amines which capture CO2 at a 2:1 molar ratio, thus making the immobilized DBU solid Sorbents competitive with existing commercially available Sorbents and liquid amine-based capture systems. The immobilized DBU solid Sorbents prepared in this study exhibit acceptable CO2 capture capacities of 3.0 mol CO2/kg Sorbent at 298 K; however, at the critical operational temperature of 338 K, the capacity was reduced to 2.3 mol/kg Sorbent. The DBU Sorbents did exhibit acceptable stability over the adsorption/desorption temperature range of 298–360 K based on XPS and TGA analyses.
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Capture of carbon dioxide by solid amine Sorbents
International Journal of Environmental Technology and Management, 2004Co-Authors: Mcmahan L. Gray, Henry W. Pennline, Y. Soong, K. J. Champagne, John P. Baltrus, Robert W. Stevens, Rajesh Khatri, Steven S. C. ChuangAbstract:The reaction of tetraethylorthrosilcate (TEOS) with y-aminopropyltriethoxysilane (APTS) has produced stable solid amine Sorbents for the capture of carbon dioxide. The resulting amine-enriched silicon Sorbent (SBA-15) has been proven to be competitive with existing environmental CO2 controlled life Sorbents based on the immobilised amine technology. XPS analysis has indicated that the amine groups (N1s Peak) were incorporated onto the surfaces of this amine-based Sorbent in the range of 7%. The performance of the SBA-15 was comparable to the commercially available immobilised amine Sorbent (IAS).
