Study on combustion characteristics and the migration of heavy metals during the co-combustion of oil sludge char and microalgae residue

Recycling of waste biomass energy has attracted more and more attention. Oil sludge char (OS char) combustion blended with microalgae residue (MR) is a clean, effective method for recycling energy. The co-combustion and kinetics analysis were conducted on a thermogravimetric analyzer (TGA). The simulation calculation and potential toxicity of heavy metals in the co-combustion process were investigated. Results showed that adding MR could improve the combustion performance of OS char. The average activation energy of OS char, MR and the mixture was 121.28 kJ mol(-1), 153.43 kJ mol(-1), and 142.24 kJ mol(-1), respectively. The KAS and Starink methods were more accurate than the FWO method. Besides, the risk assessment results indicated the risk index (RI) values of MR and fly ash at 1100 degrees C were at a considerable risk level of 140.33 and 109.50, respectively. Simulation results demonstrated that the synergistic removal of arsenic (As) and nitrogen (N) could be achieved by moderately controlling temperature. Furthermore, MR addition could significantly reduce the content of chlorine (Cl) in the mixture, decreasing the generation of gaseous ZnCl2 and PbCl2. The results will supply essential data and theoretical support for the high-value utilization and low heavy metal emissions of biomass waste. (C) 2019 Published by Elsevier Ltd.