Utilization of Alumina Aerogel as High Surface Area Support for the Fabrication of Oxygen Carriers in the Chemical Looping Combustion Process

2019 ◽  
Vol 33 (6) ◽  
pp. 5408-5414 ◽  
Author(s):  
Davood Karami ◽  
Nader Mahinpey
Keyword(s):  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Combustion Process ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Oxygen Carriers ◽  
Alumina Aerogel

scholarly journals Characterization for Disposal of the Residues Produced by Materials Used as Solid Oxygen Carriers in an Advanced Chemical Looping Combustion Process

2018 ◽  
Vol 8 (10) ◽  
pp. 1787
Author(s):  
Adriana Carrillo ◽  
Carmen Forero
Keyword(s):  
Manganese Oxides ◽  
Negative Impact ◽  
Low Cost ◽  
Combustion Process ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Oxygen Carriers ◽  
Additional Energy ◽  
General Terms ◽  
Solid Oxygen

Chemical looping combustion (CLC) is a technology that is part of the capture and storage of CO2 through the combustion with solid oxygen carriers (OCs). It is considered an energy-efficient alternative to other methods, since it is a technology that inherently separates CO2 and has the advantage of not requiring additional energy for this separation. The key to the performance of CLC systems is the OC material. Low-cost materials, i.e., natural minerals rich in metal oxides (chromite, ilmenite, iron, and manganese oxides) were used in this investigation. These may contain traces of toxic elements, making the carrier residues hazardous. Therefore, the oxidized and reduced-phase residues of six OCs, evaluated in a discontinuous batch fluidized bed reactor (bFB) using methane and hydrogen as the reducing gas, were characterized by several techniques (crushing strength, SEM, XRD, and XRF). The researchers found that, in general terms, the residues present a composition very similar to that reported in the fresh samples, and although they contain traces of Ba, Cu, Cr, Ni or Zn, these compounds do not migrate to the leachate. It was mainly found that, according to the current regulations, none of the residues are classified as toxic, as they do not exceed the permissible limits of metals (100 and 5 mg/L for Ba and Cr, respectively), with 3.5 mg/L the highest value found for Ba. Thus, they would not have a negative impact on the environment when disposed of in a landfill.

scholarly journals Synthesis of Wollastonite Powders by Combustion Method: Role of Amount of Fuel

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Imarally V. de S. R. Nascimento ◽  
Willams T. Barbosa ◽  
Raúl G. Carrodeguas ◽  
Marcus V. L. Fook ◽  
Miguel A. Rodríguez
Keyword(s):  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Combustion Process ◽  
Calcium Nitrate ◽  
Combustion Method ◽  
Thermal Treatments ◽  
X Ray Diffraction ◽  
Solution Combustion

The objective of this work has been the synthesis of wollastonite by solution combustion method. The novelty of this work has been obtaining the crystalline phase without the need of thermal treatments after the synthesis. For this purpose, urea was used as fuel. Calcium nitrate was selected as a source of calcium and colloidal silica served as a source of silicon. The effect of the amount of fuel on the combustion process was investigated. Temperature of the combustion reaction was followed by digital pyrometry. The obtained products were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and specific surface area. The results showed that the combustion synthesis provides nanostructured powders characterized by a high surface area. When excess of urea was used, wollastonite-2M was obtained with a submicronic structure.

The Performance Research on Reaction of Fe2O3/Al2O3 Oxygen Carrier and CO in Chemical-Looping Combustion Process

2012 ◽  
Vol 550-553 ◽  
pp. 974-978
Author(s):  
Wen Yan Li ◽  
Xing Lei Liu ◽  
Qiu Luan Chen ◽  
Feng Ming Chu
Keyword(s):  
Oxygen Carrier ◽  
Combustion Process ◽  
Kinetic Mechanism ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Oxygen Carriers ◽  
Novel Technology ◽  
Mechanism Function ◽  
Tg And Dtg ◽  
Performance Research

Chemical-looping combustion (CLC) is a novel technology, which has inherent property of separating the greenhouse gas CO2, which uses oxygen carriers to transfer oxygen for combustion from air to fuel. The reactivity of Fe2O3/Al2O3 oxygen carrier was assessed by measuring their ability to oxidize CO. The kinetics and mechanism of oxygen carrier have been studied by TG and DTG techniques. The kinetic mechanism function of the reaction between Fe2O3/Al2O3 and CO has been built using the Coats-Redfern equation.

The Preparation Methods of Fe2O3/Al2O3 Oxygen Carriers and their Chemical Looping Combustion Performance

2013 ◽  
Vol 724-725 ◽  
pp. 1145-1149 ◽  
Author(s):  
Zi Song Liu ◽  
Yong Gang Wei ◽  
Kong Zhai Li ◽  
Hua Wang ◽  
Xing Zhu ◽  
...  
Keyword(s):  
High Selectivity ◽  
Oxygen Carrier ◽  
Combustion Process ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Oxygen Carriers ◽  
Preparation Methods ◽  
Air Atmosphere ◽  
Infrared Gas Analyzer ◽  
Structure And Activity

60wt%Fe2O3/Al2O3oxygen carriers were prepared by different methods and characterized by means of XRD, H2-TPR, infrared gas analyzer. The effects of preparation methods on the structure and activity of Fe2O3/Al2O3oxygen carriers for chemical looping combustion of methane were also investigated. The factors on the selectivity of CO2in the chemical looping combustion process at different reaction temperatures were discussed. Methane can be quickly converted to CO2and H2O with high selectivity at 850°C for 15 min. After redox cycling in alternant methane/air atmosphere for 30 times, the formation of CO2was enhanced, indicating higher activity of oxygen carrier after the redox experiment.

Study and Improvement of the Regeneration of Metallic Oxides Used as Oxygen Carriers for a New Combustion Process

2006 ◽  
Vol 4 (1) ◽  
Author(s):  
Sebastien Roux ◽  
Ammar Bensakhria ◽  
Gerard Antonini
Keyword(s):  
Oxygen Carrier ◽  
Combustion Process ◽  
Reactive Oxygen ◽  
Chemical Looping Combustion ◽  
Regeneration Ability ◽  
Chemical Looping ◽  
Oxygen Carriers ◽  
Air Oxidation ◽  
Metallic Oxide ◽  
Metallic Oxides

A new combustion process called chemical-looping combustion, has been suggested as an energetically efficient method for separation and capture of the carbon dioxide, generated by the combustion of fossil's fuels. This process consists of a reversible combustion, based on successive fuel oxidation via the reduction of metallic oxide followed by its regeneration by air oxidation. The generated products are: the reduced oxygen carrier, which is regenerated in a second reactor by air and recycled, and a flue gas, mainly composed of CO2 and H2O, which could be separated by condensation.In chemical-looping combustion process, it is important that the metallic oxide, used as an oxygen carrier, has a high reactivity with the fuel and good regeneration ability. It should have also good mechanical characteristics, in order to avoid its attrition and agglomeration during the successive cyclic reactions.In this work, the reactivity study of various oxygen carriers was carried out, during ten successive oxidation and reduction cycles, using a thermal gravimetrical analysis apparatus. From the results obtained, two types of oxygen carriers were identified: very reactive oxygen carriers, with a decreasing of their reactivity during the successive cycles of reduction and oxidation, and oxygen carriers with low and constant reactivity during the successive cycles.In order to improve the capacity of regeneration of the reactive oxygen carrier, several mixtures were prepared by adding stable and non-reactive metallic oxide, which acts as binder or doping agent by the mechanical properties of the mixed oxygen carrier improvement.The results obtained showed that, for all mixtures prepared and tested, the addition of binders to the reactive metallic oxides improve their regeneration ability. The best results, concerning the reactivity and the regeneration performances, were obtained with Fe2O3 mixed with CaO, TiO2 or MgO, followed by NiO mixed with CaO or TiO2 and finally CuO mixed with TiO2 or MgO.

Comparison of Chemical-Looping with Oxygen Uncoupling and Chemical-Looping Combustion Technology Reaction Mechanism

2014 ◽  
Vol 955-959 ◽  
pp. 2261-2266
Author(s):  
Xiao Ning Gao ◽  
Hui Min Xue ◽  
Yuan Li ◽  
Xue Feng Yin
Keyword(s):  
New Technologies ◽  
Oxygen Carrier ◽  
Combustion Process ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Oxygen Carriers ◽  
High Efficient ◽  
Direct Separation ◽  
Fuel Reactor ◽  
Combustion Technology

In order to reduce the emission of CO2and control the global greenhouse effect, the paper introduces and compares two new technologies named chemical-looping combustion (CLC) and chemical-looping with oxygen uncoupling (CLOU) that are both high-efficient and clean. Through comparative analysis, CLC has been widely studied because of its direct separation of CO2, reduction loss of the heat, improvement of energy efficiency and avoiding of the generation of fuel type NOxin the combustion process. Besides the current research for metal oxygen carrier, there are some scholars find various non-metal oxygen carriers that have the better performance in CLC. But the study on reactors of CLC is still not mature, especially the solid fuel reactor, which is different from CLOU. In a certain sense, CLOU is an improved technology based CLC, besides the bove advantages, it also can react with coal directly. Many scholars use coal as fuel in the fluidized bed by the technology of CLOU, and the results of them are feasible. So from this perspective, CLOU technology has more broad prospects than CLC in the China.

High surface area alumina aerogel at elevated temperatures

1994 ◽  
Vol 90 (17) ◽  
pp. 2573 ◽  
Author(s):  
Tatsuro Horiuchi ◽  
Toshihiko Osaki ◽  
Toyohiko Sugiyama ◽  
Hiroyuki Masuda ◽  
Masakazu Horio ◽  
...  
Keyword(s):  
Surface Area ◽  
Elevated Temperatures ◽  
High Surface ◽  
High Surface Area ◽  
Alumina Aerogel
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