Chemical looping processes — particle characterization, ionic diffusion-reaction mechanism and reactor engineering

Abstract

The chemical looping strategy for fossil energy applications promises to achieve an effi cient energy conversion system for electricity, liquid fuels, hydrogen, and/or chemical generation while economically separating CO 2 by looping reaction design in the process. Two types of chemical looping technologies have been developed based on two different reactions of chemical looping intermediates. Type I chemical looping systems utilize metal and metal oxide reductionoxidation properties to perform the looping reactions. Type II chemical looping systems utilize metal oxide and metal carbonate carbonation-calcination properties to perform the looping reactions. The type of metal or metal oxide along with their preparation methods for applications in both types of chemical looping systems plays signifi cant roles in the chemical looping technology performance. Understanding the reaction mechanism associated with looping intermediates in both types of reactions is important to the rate process of reactions, in turn affecting the design of the looping particles. Furthermore, as conversions of gaseous and solid reactants are closely associated with their contact modes, the intricate contact mode plays an important role in determining the reactant conversions and hence the solid reactant fl ux in the reactors. The purpose of this paper is thus to provide a perspective on the two key aspects of chemical looping technology, which are not well reported in the literature, namely, reaction mechanism and reactor engineering.

110th Anniversary: Carbon Dioxide and Chemical Looping: Current Research Trends

“…For a detailed overview of progress and challenges in scale-up of chemical looping processes, the interested reader is referred elsewhere. 127,130,258,260,272,282…”

Progress in oxygen carrier development of methane-based chemical-looping reforming: A review

“…The heat released from the reaction can be first utilized to compensate any heat duty from the reducer, and then the excess heat can be subjected to producing electricity and meeting the parasitic energy demand. However, the oxidation of OCs using air is generally carried out in a dilute bed regime, making the conversion of oxidant less important [6,7]. In addition to air, steam and CO 2 have been widely considered as oxidants although the oxidation kinetics of both steam and CO 2 are significantly slower than air [36].…”

“…However, the combustion of fossil fuels is widely considered as a leading cause for CO 2 emissions, which is the main contributor to global warming effect [2][3][4][5]. Among current and emerging technologies for CO 2 capture, chemical-looping combustion (CLC) is a particularly promising approach [6,7]. The first step of CLC involves the reduction of metal oxide (also named as oxygen carrier, OC), MO, in contact with a fuel in one reactor (fuel reactor, FR).…”

Perovskite ceramics and recent experimental progress in reactor design for chemical looping combustion application

“…These particles also should be non-toxic, economically viable and environmentally benign. Their melting temperature should also be a matter of concern (Arjmand et al, 2014a;Hossain & de Lasa, 2008;Zeng et al, 2012). Trial and error and heuristic methods have generally been used for producing oxygen carriers to date.…”