Assessment of low-cost oxygen carrier in South-western Colombia, and its use in the in-situ gasification chemical looping combustion technology

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 Narino 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 H-2 at 950 degrees C during 50 cycles. A good behaviour was observed with CO and H-2, with a moderate attrition, and lifetime of 2950 h. The material presented a trend towards agglomerating with CH4, and no agglomeration with CO and H-2. 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 degrees C interval when the material was oxidized with a 10 vol% O-2. Due to its good performance with CO and H-2, 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 degrees C to 1000 degrees C. Its good behaviour with H-2 and CO makes it a promising OC for iG-CLC technology.