Uso da glicerina no processo de combustão por recirculação química - um estudo experimental e de simulação

Abstract

Greenhouse gases emissions and their consequences are one of the main environmental problems faced today. To mitigate the impacts caused by this phenomenon, Brazil seeks to reduce CO2 emissions by 43% by 2030 in order to meet the Paris Agreement. To achieve this goal, it is possible to use technologies based on the principle of Carbon Capture and Storage, such as Chemical Looping Combustion (CLC). These processes are versatile in terms of the use of fuels in the three states of matter and with the growing availability of glycerin in recent years, there is a need to relocate this by-product to other applications that could increase its market value, since this waste product represents about 10% of the amount of biodiesel generated. Thus, this study aims to evaluate the feasibility of glycerin on Chemical Looping Combustion and provide its process simulation. The crude glycerin solution was synthesized considering water, methanol and ethanol as the main contaminants. The experiments were carried in two sets: the first to determine the best values to oxygen-to-fuel molar ratio (ϕ), H2O/Glycerin molar ratio and Fuel Reactor Temperature (TFR) and afterwards another set of experiments was done for the contaminants (methanol and ethanol) using the best operational conditions determined by the previous set. A simulation of the CLC process was developed in the Aspen Plus® environment, verified with methane and ethanol experimental data and adjusted for glycerin. For the first set, the results revealed that the optimized conditions for the diluted glycerin in CLC was achieved at ϕ = 7, H2O/Glycerin = 0,75 e TRR = 1023 K. The impurities analyses show that methanol brings disadvantages to the combustion process, while ethanol improves the combustion efficiency. The process simulation was capable to reproduce the experimental data found for glycerin with acceptable deviations (mean deviation around 3% for the combustion efficiency).