Oil sludge (OS) pyrolysis was conducted with a tube furnace reactor. Production distributions and compositions were investigated under different conditions of pyrolysis temperature, heating mode, and atmosphere (N2/CO2). Little change was detected with the product yields of char, oil, and gas when the final temperature exceeded 600 °C. Compared with slow pyrolysis, oil and char yields decreased and gas yield increased in fast pyrolysis. CO2 could promote OS pyrolysis, resulting in a reduction of char yield. SEM images showed that the surface of OS was smooth with a dense texture while the surface of OS char was rough with a well-developed pore structure that formed after pyrolysis. Simulated distillation results showed that light fractions from OS pyrolysis were more than 30% higher than those of oil from OS extraction. With the increase of pyrolysis temperature, light fractions (gasoline, diesel, and jet fuel) in pyrolysis oil decreased. During fast pyrolysis, the heavy fractions produced can be cracked into light fractions. The content of light fractions was 46% compared with 34% for oil from slow pyrolysis. It did not differ much with the oil product distributions from pyrolysis in inert (N2) and CO2 atmosphere. The yields of C4–6 and C6 were higher than those of CH4 in slow pyrolysis between 500 and 700 °C. Fast pyrolysis and CO2 atmosphere favored the conversion of stable macromolecules to short chain methyl compounds, resulting in a higher CH4 yield.

No abstract

The pyrolysis of oil sludge (OS) with microalgae residue (MR) additive was conducted with a TGA and a tube furnace. The pyrolysis process of OS with the MR additive can be divided into three stages: 1) water evaporation, 2) the release of light groups of hydrocarbon compounds, the cracking of heavy groups, and carbon decomposition, and 3) minerals decomposition. With the MR addition ratio increasing, the yield of oil and gas increased, and oil to gas ratio increased during OS pyrolysis. The MR addition improved the quality of pyrolysis oil and gas from OS pyrolysis. The proportion of light oil increased from 38 % with a 5 % MR addition ratio to 45 % with a 30 % addition ratio. Major components of pyrolysis gas included H 2 , CO, CO 2 , and C x H y . With the increase of the MR blending ratio, CO and CO 2 contents increased, while H 2 and C x H y contents decreased. Adding MR favoured the transformation of heavy hydrocarbons (C 6þ ), resulting in a high content of light hydrocarbons. This work can help promote massive synergistic treatment of OS and microalgae biomass.

No abstract