Thermodynamic and Kinetic Analysis of Ca-Based Oxygen Carrier in Chemical-Looping Combustion

2010 ◽  
Vol 8 (1) ◽  
Author(s):  
Chang Jing ◽  
Cui Dejie
Keyword(s):  
Kinetic Analysis ◽  
Oxygen Carrier ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Calcium Sulfide ◽  
Oxygen Carriers ◽  
Thermo Gravimetric ◽  
Caso4 Oxygen Carrier ◽  
Carbon Dioxide Co2 ◽  
Gravimetric Apparatus

Chemical-looping combustion (CLC) is a promising technology to capture carbon dioxide (CO2) inherently and conveniently without the additional apparatus. At present, for some metal oxide oxygen carriers, the high costs and the positive hazards to the environment inhibit the developing of CLC systems. The feasibility of using CaSO4 oxygen carrier in the CLC system is studied in this paper. Through the thermodynamic analysis, the carbon deposition and the sulfur evolution are studied in the reaction between CaSO4 and a typical syngas. In addition, providing that hydrogen (H2) is fed as the gaseous fuel in the CLC system, the kinetic analysis is investigated on the reduction of CaSO4 by H2 and the oxidation of calcium sulfide (CaS) by oxygen (O2) through the thermo-gravimetric apparatus (TGA). The kinetic models are built on the reduction and the oxidation of the oxygen carrier. The results calculated from the models agree well with the experimental data. Finally, the possible reaction mechanisms for the reduction and the oxidation are explored.

Experimental Investigation of Chemical Looping Combustion of CO with Fe-Based Oxygen Carrier

2014 ◽  
Vol 986-987 ◽  
pp. 72-75
Author(s):  
Qu Li ◽  
Chang Feng Lin ◽  
Jun Jiao Zhang ◽  
Wei Liang Cheng ◽  
Wu Qin
Keyword(s):  
Experimental Investigation ◽  
Oxygen Carrier ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Oxygen Carriers ◽  
Thermo Gravimetric ◽  
Cu Doping ◽  
X Ray

Reaction activities of Ni-doped and Cu-doped Fe2O3 oxygen carriers (OCs) with CO were investigated using thermo gravimetric (TG-DTG).The structures of the prepared OC were characterized by X-ray diffract meter (XRD).TG-DTG investigations indicated that rational Ni and Cu doping could efficiently enhance the reactivity of Fe-base oxygen carrier for oxidizing CO under different conditions. And Fe-based OC doped with 20 wt. % Ni can realize the highest reactivity.

Effect of Fuel and Oxygen Carriers on the Hydrodynamics of Fuel Reactor in a Chemical Looping Combustion System

2013 ◽  
Author(s):  
Atal B. Harichandan ◽  
Tariq Shamim
Keyword(s):  
Oxygen Carrier ◽  
Bubble Formation ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Calcium Sulfide ◽  
Oxygen Carriers ◽  
Fuel Reactor ◽  
Gas Interactions ◽  
Kinetics Of ◽  
Good Agreement

The hydrodynamics of fuel reactor in a chemical looping combustion (CLC) system has been analyzed by using a multiphase CFD-based model with solid-gas interactions and chemical reactions. In this paper, the fuel reactors of two CLC systems are numerically simulated independently by using hydrogen with calcium sulfide as oxygen carrier, and methane with nickel as oxygen carrier in similar conditions. Kinetic theory of granular flow has been adopted. Conservation of mass, momentum and species equations, and reaction kinetics of oxygen carriers are used for the numerical calculation. The present results obtained are in good agreement with the experimental and numerical results available in open literature. The bubble hydrodynamics in both the fuel reactors are analyzed. The salient features of bubble formation, rise and burst are prominent in hydrogen-fueled reactor as compared to methane-fueled reactor. The fuel conversion rate is found to be larger in the case of hydrogen-fueled reactor.

Investigation into compound CaSO4 oxygen carrier for chemical-looping combustion

2011 ◽  
Vol 39 (3) ◽  
pp. 161-168 ◽  
Author(s):  
Ning DING ◽  
Ying ZHENG ◽  
Cong LUO ◽  
Qi-long WU ◽  
Pei-fang FU ◽  
...  
Keyword(s):  
Oxygen Carrier ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Caso4 Oxygen Carrier

Chemical-looping combustion of methane with CaSO4 oxygen carrier in a fixed bed reactor

2008 ◽  
Vol 49 (11) ◽  
pp. 3178-3187 ◽  
Author(s):  
Qilei Song ◽  
Rui Xiao ◽  
Zhongyi Deng ◽  
Huiyan Zhang ◽  
Laihong Shen ◽  
...  
Keyword(s):  
Oxygen Carrier ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Caso4 Oxygen Carrier

scholarly journals Chemical Looping Combustion of Methane: A Technology Development View

2013 ◽  
Vol 2013 ◽  
pp. 1-15 ◽  
Author(s):  
Rutuja Bhoje ◽  
Ganesh R. Kale ◽  
Nitin Labhsetwar ◽  
Sonali Borkhade
Keyword(s):  
Technology Development ◽  
Oxygen Carrier ◽  
Clean Energy ◽  
Unit Weight ◽  
Chemical Looping Combustion ◽  
Process Conditions ◽  
Net Energy ◽  
Chemical Looping ◽  
Oxygen Carriers ◽  
Byproduct Formation

Methane is a reliable and an abundantly available energy source occurring in nature as natural gas, biogas, landfill gas, and so forth. Clean energy generation using methane can be accomplished by using chemical looping combustion. This theoretical study for chemical looping combustion of methane was done to consider some key technology development points to help the process engineer choose the right oxygen carrier and process conditions. Combined maximum product (H2O + CO2) generation, weight of the oxygen carrier, net enthalpy of CLC process, byproduct formation, CO2emission from the air reactor, and net energy obtainable per unit weight (gram) of oxygen carrier in chemical looping combustion can be important parameters for CLC operation. Carbon formed in the fuel reactor was oxidised in the air reactor and that increased the net energy obtainable from the CLC process but resulted in CO2emission from the air reactor. Use of CaSO4as oxygen carrier generated maximum energy (−5.3657 kJ, 800°C) per gram of oxygen carrier used in the CLC process and was found to be the best oxygen carrier for methane CLC. Such a model study can be useful to identify the potential oxygen carriers for different fuel CLC systems.

scholarly journals Comparison of oxygen carriers for chemical-looping combustion

2006 ◽  
Vol 10 (3) ◽  
pp. 93-107 ◽  
Author(s):  
Marcus Johansson ◽  
Tobias Mattisson ◽  
Anders Lyngfelt
Keyword(s):  
Fossil Fuels ◽  
Oxygen Carrier ◽  
High Reactivity ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Oxygen Carriers ◽  
Reducing Conditions ◽  
Different Temperatures ◽  
Combustion Technology ◽  
Separation Of Co2

Chemical-looping combustion is a combustion technology with inherent separation of the greenhouse gas CO2. This technique involves combustion of fossil fuels by means of an oxygen carrier which transfers oxygen from the air to the fuel. In this manner a decrease in efficiency is avoided for the energy demanding separation of CO2 from the rest of the flue gases. Results from fifty oxygen carriers based on iron-, manganese- and nickel oxides on different inert materials are compared. The particles were prepared using freeze granulation, sintered at different temperatures and sieved to a size 125-180 mm. To simulate the environment the particles would be exposed to in a chemical-looping combustor, reactivity tests under alternating oxidizing and reducing conditions were performed in a laboratory fluidized bed-reactor of quartz. Reduction was performed in 50% CH4/50% H2O while the oxidation was carried out in 5% O2 in nitrogen. In general nickel particles are the most reactive, followed by manganese. Iron particles are harder but have a lower reactivity. An increase in sintering temperatures normally leads to an increase in strength and decrease in reactivity. Several particles investigated display a combination of high reactivity and strength as well as good fluidization behavior, and are feasible for use as oxygen carriers in chemical-looping combustion.

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