Research Progress and Perspectives of Solid Fuels Chemical Looping Reaction with Fe-Based Oxygen Carriers

Abstract

Chemical looping (CL) is regarded as a promising technology in industrial applications, because of its inherent characteristic of CO 2 capture. The technique of CL is applied in solid fuels fields, including chemical looping combustion (CLC), chemical looping gasification (CLG), chemical looping reforming (CLR), chemical looping water splitting (CLWS), and oxygen carrier aided combustion (OCAC). Oxygen carrier is a core media in chemical looping reaction, which plays the role of transporting oxygen and has the function of decreasing the energy penalty of air separation. Among all oxygen carriers, ironbased (Fe-based) materials are of most possibilities to be applied in industrial field, because of its economical and eco-friendly characteristics. Some reviews have reported the Fe-based oxygen carrier in CL application. However, the related preparation methods, overall application of CL and theoretical reaction calculation of Fe-based oxygen carriers have not been covered comprehensively. In this Review, the general view of Fe-based oxygen carrier including iron ores and artificial synthesis are reviewed. In addition, the different synthesis methods of Fe-based oxygen carrier are meticulously and profoundly summarized, involving mechanical mixing, impregnation, spraying drying, freeze granulation, sol−gel, solution combustion, and coprecipitation method. Then, the characteristics of Fe-based oxygen carrier from the perspectives of thermodynamics, redox kinetics analysis, antisintering and wear property of iron oxides are discussed in detail. Furthermore, the chemical looping reaction mechanism of Fe-based oxygen carriers is reviewed from the perspectives of reaction and oxygen carrier migration mechanism. Moreover, this review summarizes the application of Fe-based oxygen carrier in CLC, CLG, CLR, CLWS, and OCAC. And the recent progress of reaction mechanism of oxygen carrier by density functional theory (DFT) calculations and machine learning are further presented. Finally, the challenges and prospects for Fe-based oxygen carrier with the corresponding effective strategies are proposed. It is expected that this Review may provide insights into the Fe-based oxygen carrier and the practical application of chemical looping.

Carbon Dioxide Capture and Hydrogen Production with a Chemical Looping Concept: A Review on Oxygen Carrier and Reactor

“…Using chemical looping technology, high-purity H 2 is produced by reforming carbon-containing fuels with steam in separated reactors. This technology is called chemical looping steam reforming (CLSR) and is illustrated in Figure . , Compared with CLC, CLSR can simultaneously produce high-purity H 2 and syngas with adjustable C/H ratio, further increasing the economic value of this type of chemical looping technology . CLSR also partially oxidizes hydrocarbons using lattice oxygen in the OC, and subsequently, the reduced OC is oxidized by steam in an oxidizer, thereby splitting water into H 2 and lattice oxygen ().…”

“…37,38 Compared with CLC, CLSR can simultaneously produce high-purity H 2 and syngas with adjustable C/H ratio, further increasing the economic value of this type of chemical looping technology. 39 CLSR also partially oxidizes hydrocarbons using lattice oxygen in the OC, and subsequently, the reduced OC is oxidized by steam in an oxidizer, thereby splitting water into H 2 and lattice oxygen (R7). Similar to the CLDR technology introduced in the previous section, the oxidizing ability of steam is weak, so an additional combustor can be introduced after the oxidizer to fully replenish the consumed lattice oxygen.…”

Review on Migration and Transformation of Lattice Oxygen during Chemical Looping Conversion: Advances and Perspectives

“…Febased OCs have received a lot of attention due to their abundance of lattice oxygen, several oxidation states of Fe during the reduction process, low cost, and environmental friendliness. Fe-based OCs have different synthesis methods, which result in different properties; 85 different synthesis methods result in different microstructures and lattice oxygen transfer pathways. CeO 2 is an excellent redox catalyst for selective oxidation through the Ce 4+ /Ce 3+ redox couple.…”

Experimental Investigation on Chemical Looping Co‐Gasification of Water Hyacinth and Solid Wastes

“…Until now, iron‐based OCs become one of the most promising OCs because of their inexpensive and well performed. [ 42,48 ]…”

“…[38,39] Generally speaking, OCs need to possess characteristics such as strong oxygen-carrying capacity, high reactivity, good wear resistance, and good anti-sintering ability. [40][41][42][43] Meanwhile, combined with economic and environmental benefits, the cost and environmental friendliness should also be considered. [44,45] Many scholars have investigated the selection of OC.…”