Assessment of low-cost oxygen carrier in South-western Colombia, and its use in the in-situ gasification Chemical Looping Combustion technology

© 2018. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/In Chemical Looping Combustion (CLC), the Oxygen Carrier (OC) is key element of the process. Most OCs have been developed synthetically, using an active metal oxide combined with an inert material. When solid fuels are used, a loss of OC is expected as it mixes with the ashes generated during the CLC process making the costs elevated. As a result, there is a growing interest in using low-cost OCs based in Mn and Fe. In this research, a by-product derived from manganese ore purification is studied. This material has a high silicon content and it is composed of rhodonite as the main specie and wustite as the minority specie. The material, a Mn mineral from the Nariño department in the Southwest of Colombia, was selected in a previous work based on its good properties such as appropriate crushing strength, an oxygen transport capacity of 3,4 %, and a relatively high reactivity. Here, tests in a batch fluidized bed reactor were carried out with the selected material with CH4, CO, and H2 at 950°C during 50 cycles. A good behaviour was observed with CO and H2, with a moderate attrition, and lifetime of 2950 hours. The material presented a trend towards agglomerating with CH4, and no agglomeration with CO and H2. The possible oxygen uncoupling effect due to the presence of combined oxides of manganese and silicon was also evaluated, but there was no evidence in the 950-1040 ºC interval when the material was oxidized with a 10 vol.% O2. Due to its good performance with CO and H2, the material was evaluated for the in-situ Gasification Chemical Looping Combustion (iG-CLC) technology, using a Chilean reactive coal as fuel at temperatures from 900 °C to 1000 °C. Its good behaviour with H2 and CO makes it a promising OC for iG-CLC technology.This research was conducted with financial support from the Unión Temporal Incombustion (Temporary Joint Working Group) and Colciencias through the Contract of Contingent Recovery RC 0852-2012 and to the collaboration of Instituto de Carboquímica (CSIC) from Zaragoza. Thanks to Ing. Konrad Holscher from Mina Invierno (Chile) for supplying the subbituminous coal batch.Peer reviewe