Effect of Production Parameters on the Spray-Dried Calcium Manganite Oxygen Carriers for Chemical-Looping Combustion

Abstract

The oxygen carrier CaMn0.9Mg0.1O3−δ was successfully tested in different chemical-looping units. High methane conversion and oxygen uncoupling properties have been found for this type of material. Most of the CaMn0.9Mg0.1O3−δ oxygen carrier particles tested so far have been produced using the spray-drying method. In this work, the focus has been on studying the effects of production parameters on the properties of this important oxygen carrier. The effects of three production parameters, i.e., milling time, calcination temperature, and calcination time, were examined for the spray-dried particles. The time of ball-milling for the slurry prepared for spray-drying was varied from 5 to 45 min, the calcination temperature from 1300 to 1350 °C, and the calcination time from 4 to 16 h. None of these parameters had any influence on the final crystalline phases of the oxygen carrier, yet some of the properties were clearly changed. The bulk density, crushing strength, and resistance against physical attrition can be enhanced by increasing the calcination temperature, calcination time, or milling time. Further, the BET specific surface area and porosity of the oxygen carrier particles decreased when the slurry was milled or particles were calcined for extended periods. The average methane conversion of the oxygen carrier varied in a wide range, from 99% to 55% at 950 °C, depending upon the production parameters used. However, no obvious influence of the examined production parameters was observed for the oxygen uncoupling property of the oxygen carrier, which may be due to the thermodynamic limitation during testing.

Manufacturing of Perovskite Oxygen Carriers by Spray Granulation for Chemical Looping Combustion

“…Overall, these results are in good agreement with the observations of Jing et al. on CaMn 0.9 Mg 0.1 O 3− δ made by spray drying …”

“…Thes pecific surface area of granules as af unction of temperature andd uration of the sintering step is shown inFigure 6. Thes pecific surface area is rather low,a se xpected from the synthesis method, and clearlyd ecreases with both sinteringt emperature and sinteringt ime.O verall,t hese results are in good agreement with the observations of Jing et al on CaMn 0.9 Mg 0.1 O 3Àd made by spray drying [39].…”

Oxygen‐Carrier Development of Calcium Manganite–Based Materials with Perovskite Structure for Chemical‐Looping Combustion of Methane

“…In both projects, different research groups contributed with their expertise to the development of calcium manganite–based materials. In the Innocuous project, this involved investigations of redox kinetics and sulfur tolerance, material screening and evaluation of spray‐drying parameters using batch testing, and continuous operation in two chemical‐looping combustors with nominal fuel inputs of 300 W and 10 kW . At a larger scale, the materials C14 (CaMn 0.9 Mg 0.1 O 3− δ ) and C28 (CaMn 0.775 Mg 0.1 Ti 0.125 O 3− δ ) were investigated in a 120 kW CLC unit .…”

Fabrication process parameters significantly affect the perovskite oxygen carriers materials (OCM) performance in chemical looping with oxygen uncoupling (CLOU)

“…The most important parameters affecting sintering are temperature, time and atmosphere. These parameters were investigated in depth for this system Jing et al [38] showed that temperature has the greatest effect on the quality of the final product and that after 5-6-h sintering, the effect of time is minimal. It was also shown that for upscaled calcination, an air atmosphere should be used.…”