Analysis on integrated thermal treatment of oil sludge by Aspen Plus.

An integrated thermal treatment (coupled pyrolysis and combustion) of oil sludge (OS) was proposed for enhancing the OS resource utilization. According to the pyrolysis experiment results, the integrated thermal treatment process of OS was modeled and simulated using Aspen Plus. Carbon flow, heat distribution, energy flow, energy efficiency and exergy efficiency of the process were analyzed and discussed. The results indicated that the simulation values were consistent with the experimental ones within the pyrolysis temperature of 00-780 °C With the increase of pyrolysis temperature, the carbon flow of pyrolysis oil was firstly increased and then sharply decreased, and the maximum value was achieved at 600-650 °C. Carbon flow of pyrolysis gas was initially increased rapidly followed by a continuously decreasing growth rate, and then increased sharply above 650 °C. The maximum heating value of pyrolysis oil was obtained at 600 °C. When pyrolysis temperature exceeded 650 °C, both the pyrolysis gas production rate and the gas heating value were improved. The energy and the exergy efficiency of the system can reach values as high as 61-68% and 56-71%, respectively, and the maximum efficiencies were achieved at the pyrolysis temperature of 650 °C. The present work could provide valuable insights towards promoting the development of effective OS utilization processes in the near future.