Study of an Iron-Based Oxygen Carrier on the Moving Bed Chemical Looping System

Abstract

The Industrial Technology Research Institute has developed a 30 kWth moving bed chemical looping system for hydrogen production. Methane is supplied as a fuel to the reducer, and steam is supplied to the oxidizer to produce hydrogen. An iron-based oxygen carrier is used circulating between the reactors. In this study, the mechanical strength, attrition rate, and conversion rate of the oxygen carrier were tested at two Fe2O3 levels of content (40 and 60 wt %) calcined at temperatures of 1100 and 1300 °C. The oxygen carrier with the lower iron content presented the higher conversion rate of 72% at both calcination temperatures. The mechanical strength (170.5 N) and attrition rate (0.3%) of the oxygen carrier with a low Fe2O3 content were higher at the higher calcination temperature. Further, the oxygen carriers were circulated in the 30 kWth moving bed chemical looping system under ambient and high-temperature conditions. The oxygen carrier with two Fe2O3 content levels (40 and 60 wt %) at the calcination temperature of 1200 °C was employed in the attrition rate test conducted in the chemical looping system. Under the ambient temperature conditions, the average attrition rate of the oxygen carrier with a lower Fe2O3 content was lower (0.16%) than that of the oxygen carrier with a higher Fe2O3 content (0.24%). Moreover, the test results show the operating temperature has a lower level of influence on the attrition rate of the oxygen carrier.

Moving Bed Reactors: Challenges and Progress of Experimental and Theoretical Studies in a Century of Research

“…Recently, scholars have developed the moving bed reactor concept integrated with chemical looping technology on the research and pilot scales, , to produce H 2 from methane and heavy liquid hydrocarbons as carbonaceous feeds . They have also focused on the effective parameters including the type of the oxygen carrier, , the gas velocity in the moving bed configuration, and the type of the carbonaceous feed, by experimental studies , as well as mathematical modeling . Furthermore, the study on the chemical looping combustion of the biomass integrated with MBT is ongoing by many researchers. ,− It can be concluded from these studies that the CL technology integrated with MBT has high energy conversion potential and CO 2 capture ability, which can be a promising concept in different areas. ,,,,,− …”

“…They have also focused on the effective parameters including the type of the oxygen carrier, , the gas velocity in the moving bed configuration, and the type of the carbonaceous feed, by experimental studies , as well as mathematical modeling . Furthermore, the study on the chemical looping combustion of the biomass integrated with MBT is ongoing by many researchers. ,− It can be concluded from these studies that the CL technology integrated with MBT has high energy conversion potential and CO 2 capture ability, which can be a promising concept in different areas. ,,,,,− …”

“…92 The oxygen carrier should possess some essential features including being low cost and ecofriendly and having a low tendency to agglomeration, high reactivity with the carbonaceous feed and oxygen, the ability to convert the carbonaceous feed to the products, low attrition, as well as a negligible fragmentation tendency. 93 Recently, scholars have developed the moving bed reactor concept integrated with chemical looping technology on the research and pilot scales, 94,95 to produce H 2 from methane 94 and heavy liquid hydrocarbons as carbonaceous feeds. 95 They have also focused on the effective parameters including the type of the oxygen carrier, 94,96 the gas velocity in the moving bed configuration, and the type of the carbonaceous feed, 95 by experimental studies 94,95 as well as mathematical modeling.…”

Numerical Investigations of a Counter-Current Moving Bed Reactor for Thermochemical Energy Storage at High Temperatures

“…The moving bed concept is widely applied when the redox reaction of metal oxides is in focus; e.g., in chemical-looping combustion (CLC) or for iron-ore reduction in the steel-making industry. In general, a moving bed reactor presents a simple design for continuous movement of particles with the possibility to transfer sensible and thermochemical energy from the particles to a gas flow [7]. In CLC, high reaction conversion of metal oxide particles has been reported for moving bed reactors in bench-scale [8], with a thermal power of 25 kW [9] or up to 30 kW [7].…”

“…In general, a moving bed reactor presents a simple design for continuous movement of particles with the possibility to transfer sensible and thermochemical energy from the particles to a gas flow [7]. In CLC, high reaction conversion of metal oxide particles has been reported for moving bed reactors in bench-scale [8], with a thermal power of 25 kW [9] or up to 30 kW [7]. Furthermore, the moving bed design causes low mechanical stress for the particles and low parasitic losses.…”