Glycerin combustion through chemical looping

Overview of the Chemical Looping Combustion coupled to the biodiesel industry. [Display omitted] •Glycerin combustion achieved in the CLC process can be nearly 100%.•Once the oxygen availability is optimized, the temperature does not affect the CLC performance using glycerin.•The carbon capture achieved values higher than 96.9% in most experiments.•Water inhibits the carbon deposition and a minimum should be added to not prejudice the CLC performance.•Ethanol can slightly improve the performance of CLC, while methanol does not favor the CLC process. Greenhouse gas 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 43% of its CO2 emissions by 2030 in order to meet the Paris Agreement. To achieve this goal, it is possible to use technologies based on the Carbon Capture, Utilization and Storage (CCUS) concept, such as Chemical Looping Combustion (CLC). The CLC can use natural wastes and industrial residues as carbon sources such as biomass, biogas and heavy oils. Glycerin, a by-product that accounts for almost 10% of all products from the biodiesel industry, can be used in this process since its availability is increasing over the years. Glycerin has a heat of combustion higher than ethanol and methane. This study aims to evaluate the feasibility of using glycerin in Chemical Looping Combustion. The crude glycerin was synthesized considering water, methanol and ethanol as the main contaminants. The fuel reactor temperature (TFR), oxygen-to-fuel molar ratio (ϕ) and H2O/Glycerin molar ratio, as well as the influence of methanol and ethanol on the performance of CLC were assessed. It was shown that the optimal performance of CLC was ϕ = 7, H2O/Glycerin = 0.75 and TFR = 1023 K, with a combustion efficiency (ηC) of 90% and complete carbon capture (carbon capture efficiency, ηCC = 100%). At these conditions, was noted that ethanol addition increased the combustion efficiency, while adding methanol caused a loss in efficiency.