Numerical Investigation of Nickel–Copper Oxygen Carriers in Chemical-Looping Combustion Process with Zero Emission of CO and H2

2019 ◽  
Vol 33 (11) ◽  
pp. 12096-12105 ◽  
Author(s):  
Junjie Lin ◽  
Kun Luo ◽  
Liyan Sun ◽  
Shuai Wang ◽  
Chenshu Hu ◽  
...  
2018 ◽  
Vol 8 (10) ◽  
pp. 1787
Author(s):  
Adriana Carrillo ◽  
Carmen Forero

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.


2012 ◽  
Vol 550-553 ◽  
pp. 974-978
Author(s):  
Wen Yan Li ◽  
Xing Lei Liu ◽  
Qiu Luan Chen ◽  
Feng Ming Chu

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.


2013 ◽  
Vol 724-725 ◽  
pp. 1145-1149 ◽  
Author(s):  
Zi Song Liu ◽  
Yong Gang Wei ◽  
Kong Zhai Li ◽  
Hua Wang ◽  
Xing Zhu ◽  
...  

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.


Author(s):  
Sebastien Roux ◽  
Ammar Bensakhria ◽  
Gerard Antonini

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.


2014 ◽  
Vol 955-959 ◽  
pp. 2261-2266
Author(s):  
Xiao Ning Gao ◽  
Hui Min Xue ◽  
Yuan Li ◽  
Xue Feng Yin

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.


2006 ◽  
Vol 45 (8) ◽  
pp. 2617-2625 ◽  
Author(s):  
Juan Adánez ◽  
Francisco García-Labiano ◽  
Luis F. de Diego ◽  
Pilar Gayán ◽  
Javier Celaya ◽  
...  

2014 ◽  
Vol 12 (1) ◽  
pp. 13-24 ◽  
Author(s):  
Hongjing Tian ◽  
Xiude Hu ◽  
Jing Chang ◽  
Mingdong Han ◽  
Guanglin Sun ◽  
...  

Abstract Calcium sulfate (CaSO4) is a promising oxygen carrier for chemical-looping combustion system. The release of sulfurous gas in the circulating of Ca-based oxygen carrier is a crucial problem. In this paper, it is found that the released amount of sulfurous gas is greatly affected by the partial pressure of reductive gas. If the partial pressure of the mixed reductive gases, composed of H2 and CO, maintains higher than 40 kPa, the sulfurous gas can be completely eliminated even at the reacting temperature higher than 1,000°C. Therefore, a new chemical-looping combustion system based on CaSO4 and NiO oxygen carrier, without any sulfur evolution, is simulated using Aspen Plus software. In the system, the syngas is generated from the steam gasification of coal and reacts with CaSO4 and NiO consecutively. The sulfur release occurred in the circulating of Ca-based oxygen carriers can be prevented because the concentrations of CO and H2 keep higher than 45% in the presence of Ca-based oxygen carriers. The suitable operating regime, in which auto-thermally operating of the system, zero-sulfur release and easy sequestration of CO2 from the flue gas are realized, is proposed in this paper. The effects of fuel reactor temperature, air reactor temperature and the recycle rate of oxygen carrier on the released heat from the system and the concentration of CO2 and H2O are also studied in the paper.


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