Recent Advances and Development of Various Oxygen Carriers for the Chemical Looping Combustion Process: A Review

Abstract

The amount of CO 2 in the atmosphere is rising due to the combustion of fossil fuels to fulfill the energy demand. The need to build cleaner and more efficient energy systems is motivated by the introduction of chemical looping combustion (CLC) as an alternative to conventional combustion by transferring oxygen. The transfer of oxygen from the air to fuel is carried out by a metal oxide known as an oxygen carrier (OC). For high fuel conversion and oxygen transport capacity, many efforts have been made for the preparation of an OC with minimal material cost. This review aims to summarize the recent advances and development of various types of OCs; particularly those developed within the previous five years are critically discussed in this paper. The main criteria for the selection of the OCs for CLC include their oxygen vacancies, oxygen transport capacities, costs, and tendencies over coke deposition, agglomeration, and attrition. OCs for CLC can be generally divided into single oxides, mixed oxides, natural mineral, spinel from mixed metal oxides, and perovskite. These have been critically discussed with their significance in CLC. The performances, advantages, and limitations of the OCs are presented and compared in detail.

Chemical Looping Combustion of Petcoke Using Two Natural Ores in a 10 kWth Continuous Pilot Plant: A Performance Comparison

“…Similarly, there are many publications that deal with the use of manganese ores as OC materials in CLC. In comparison to ilmenite, manganese ore achieved a significantly higher rate of fuel gasification and higher gas conversion, while fine production was higher. ,, High reactivity of manganese ores is often related to the catalytic effect of impurities (such as alkali particles) that causes cavitations in the solid char and improves char gasification rates as a consequence. , It should be noted that the alkali effect is not sustainable over multiple redox cycles because alkali can be lost with ash. For this reason, it is important to study the ore under long circulation periods at a pilot scale.…”

Intensified reactor for lean methane emissions treatment

“…The CL process builds upon the ability of an oxygen carrier (OC) to perform redox reactions in separate reactors or reaction stages 16 . Over numerous materials that have been studied as an oxygen carrier, Cu, Mn, Co, Ni, and Fe are the most feasible metals used for the CL process to date 27 . Several terms have been used to classify the CL process based on its particular objective, such as CL combustion 19;28;29;30 , CL gasification 31 , CL reforming 25;32;33 , CL air separation 34;35 , or based on how the oxygen is transferred such as chemical looping with oxygen uncoupling (CLOU) 23 .…”

“…), or for utilizing biomass material as feed 26 . The exploration of OC materials that have long lifetime, excellent reactivity, and lower cost, is still an area of interest in CL research 27 .…”

Comparative Study on Ni/γ-Al2O3 Prepared via Ultrasonic Irradiation and Impregnation Approaches as an Oxygen Carrier in Chemical Looping Combustion

“…9 Reports have revealed that oxygen transfer capacity and oxygen transfer rate are the most critical factors in selecting OCs. 15,16 In general, synthetic OCs consist of single metal oxides (the widely used type is the first-row transition metal oxides), mixed metal oxides, and inert support oxides. Due to their low cost and strong mechanical strength, natural occurrences such as ilmenite, olivine, iron ore, and waste materials from the industry (bauxite waste, ash, etc.)…”

“…For the past 10 years, researchers have examined various kinds of OCs that are inexpensive, thermally stable, possess good oxygen transport capacity (OTC), thermally stable, have improved mechanical strength, and better gas selectivity with a low environmental effect . Reports have revealed that oxygen transfer capacity and oxygen transfer rate are the most critical factors in selecting OCs. , …”