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In this paper, pyrolysis treatment was carried out with the tank bottom sludge of Liaohe Oilfield (LSOS) as the treatment object. Pyrolysis oil has the highest output of only 6% and the main components are gasoline and light diesel. Syngas which was the main form of energy recovery was mainly composed of CO/CO2, CH4, C2H4, etc. Temperature is the most important factor affecting energy recovery, and high-temperature environments have a positive impact on the cracking of macromolecular hydrocarbons. Increasing the temperature had a significant effect on improving the efficiency of energy recovery, which is beneficial to the recovery of energy in the form of gaseous and liquid oil. The content of organic matter in char greatly reduced, which was reflected in the significant reduction in C/H content. Part of the S/N compounds migrated and transformed, mixed into gas and liquid oil while heavy metals were enriched in char. The thermogravimetric method was carried out for the study on the pyrolysis behavior of LSOS. Starink method, KAS method and FWO method were used to calculate the kinetic parameters. The activation energy range and the average activation energy calculated by the three methods all showed high similarity, which were 61.75–237.33 kJ·mol−1, 52.58–205.63 kJ·mol−1and 59.35–207.54 kJ·mol−1 and the average values were 122.19 kJ·mol−1, 106.64 kJ·mol−1 and 112.13 kJ·mol−1, respectively. [ABSTRACT FROM AUTHOR]

In order to explore the effect of CaO on the ecological risk of chromium (Cr), copper (Cu) and zinc (Zn) in Oily sludge (OS), the incineration experiments of OS with and without calcium oxide (CaO) additive were carried out respectively in a horizontal tube furnace at the temperature ranging from 800 °C to 1000 °C. Furthermore, the ecological risk based on Risk Assessment Code (RAC) of Cr, Cu and Zn in OS, bottom ash from OS incineration (OSA) and bottom ash from OS incineration in the presence of CaO additive (OSA-CaO) were investigated in this work. The results showed that most of the Cr and Cu in OS remained in bottom ash, while Zn volatilized with the flue gas. At the same time, the RAC of Cr, Cu and Zn in OS decreased significantly after incineration. Compared with OSA, CaO obviously promoted the stabilization of Cr and Cu in OSA-CaO, but had little effect on the behavior of Zn. Moreover, CaO also reduced the RAC of Cu and Zn in samples, and reduced its harm to ecosystem. This study supplied essential data and theoretical support for the industrial treatment of OS, and was of great help to the harmless treatment of OS. [ABSTRACT FROM AUTHOR]

• The heavy metals of OS, OSA and OSA-CaO were analyzed. • The residual of Cr, Cu and Zn of bottom ash can be restrained by the increase of temperature. • The promotion effect of CaO on metal residue was in the order of Cu, Cr, Zn. • Cao can promote the transformation of Cu and Zn to more stable speciation. The volatilization of heavy metals in oil sludge (OS) restricts the development of OS incineration. In order to explore the effect of CaO on the migration characteristics of heavy metals during OS incineration, incineration experiments of OS with and without CaO were carried out respectively in a horizontal tube furnace at the temperature ranging from 800 °C to 1000 °C. The total amount, speciation fractions, and leachability of Cr, Cu and Zn in OS and bottom ash were investigated and presented in this work. The results showed that the total amount of Cr, Cu, and Zn in the bottom ash decreased with the increasing of experimental temperature. CaO could solidify the heavy metals in the bottom ash with an order of Cu, Cr, and Zn from strong to weak. In the presence of CaO additive, the exchangeable and acid-soluble fractions of Cu and Zn in bottom ash were significantly reduced. Moreover, the leaching levels of Cr, Cu and Zn in bottom ash were also obviously lowered. The results will supply essential data and theoretical support for the innocuous treatment of heavy metals in the bottom ash of OS incineration. [ABSTRACT FROM AUTHOR]

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 °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 ZnCl 2 and PbCl 2. The results will supply essential data and theoretical support for the high-value utilization and low heavy metal emissions of biomass waste. • OS char combustion mixed with MR is a promising method for energy recovery. • Simulation calculation of heavy metals migration was studied by FactSage. • MR addition improve the combustion characteristics and stability of OS char. • A moderate MR addition could significantly reduce the heavy metals ecotoxicity. • The synergistic removal of As and N elements can be achieved above 1000 °C. [ABSTRACT FROM AUTHOR]

Pyrolysis characteristics of chemical extraction microalgae residue in the presence and absence of catalysts (KCl, KOH, K 2 CO 3 , Al 2 O 3 , CaO, MgO and pyrolysis char of microalgae residue) were evaluated using a thermal analyzer and a tube furnace reactor. These catalysts can effectively improve the oil yield during microalgae residue pyrolysis. The order of the strength on increasing the oil yield was: pyrolysis char of microalgae residue > Al 2 O 3 >CaO > K 2 CO 3 >MgO > KCl > KOH. The addition of all the catalysts can effectively reduce the potential ecological risk of heavy metals in pyrolysis chars. The addition of KCl, MgO and Al 2 O 3 can increase the content of gasoline components in pyrolysis oil. All the catalysts can reduce the content of CO 2 in the pyrolysis gas, and increase the content of CO and hydrocarbon gases. KCl addition showed considerable increase in both yield and quality of pyrolysis oil and gas with a proportion of 5 wt % during microalgae residue pyrolysis. Image 104 • Catalytic pyrolysis performance of microalgae extraction residue was studied. • Catalysts reduced the potential ecological risk of the heavy metals in the char. • The order of increasing oil yield was microalgae residue pyrolysis char>Al 2 O 3 >CaO>K 2 CO 3 >MgO>KCl>KOH. • KCl showed a best catalytic performance with a proportion of 5 wt %. [ABSTRACT FROM AUTHOR]

Experimental and simulation studies on the migration characteristics of heavy metals during the incineration of OS were conducted with a tube furnace reactor and thermodynamic equilibrium calculation software FactSage, respectively. The results showed that when the incineration temperature increased from 800°C to 1100°C, the release rates of heavy metals such as Cr, Pb, Cu, Zn and Ni increased gradually and reached the maximum at 1000°C. When the excess air ratio increased from 1.0 to 1.4, the release rates of heavy metals such as Cr, Pb, Cu, Zn and Ni first decreased and then became steady. The content of gaseous hydroxide of Cr and gaseous chlorides of Pb and Cu increased while the chemical forms of Zn and Ni did not change obviously with the increase of combustion temperature or excess air ratio. [ABSTRACT FROM PUBLISHER]