Combustión de gas con captura de CO2 mediante transportadores sólidos de oxígeno basados en CuO

Abstract

Chemical looping combustion-CLC is a combustion technology with inherent separation of CO2 by using solid oxygen carriers - OC (metal oxides) in two interconnected fluidized beds, a reduction (FR) and a oxidation reactor (AR). The OC transfer the oxygen from air to fuel by avoiding direct contact between them.

This thesis has focused on the development and characterization of CuO-based oxygen carriers suitable for CLC process and to demostrate the viability of the CLC concept at pilot plant using syngas or methane as fuels. Also, the combustion of methane containing variable amounts of light hydrocarbons (LHC) of H2S was analyzed. Moreover, high temperature behavior during long-term operation of different CuO-based oxygen carriers has been also evaluated.

The evaluation of the process and the oxygen carriers was carried out in a CLC continuous unit of 500 Wth of two interconnected fluidized beds. Cu-based oxygen carriers were found to be suitable for syngas and methane combustion, reaching full gas conversion at low oxygen carrier-to-fuel ratios. Moreover, the presence of light hydrocarbons or sulfur in the fuel gas did not affect the efficiency of the process. The Cu-based oxygen carrier prepared using γAl2O3 as support modified with a small NiO addition was found to be adequate to operate at high temperatures (TFR=900ºC and TAR=950ºC) without attrition or agglomeration problems in the CLC process.

Finally, a solid waste management study of the process using Cu-based oxygen carriers was carried out. A process for the recovery and re-used of the copper content in the solid wastes was proposed and it was found that the solid wastes generated can be classified as stable non-reactive hazardous wastes which may be accepted at landfills for non-hazardous waste.