(636c) Recovery of Heavy Hydrocarbons from Indonesian Asphalt Rocks through Solvent Extraction

Recovery of heavy hydrocarbons from Indonesian
asphalt rocks through solvent extraction

Guoqiang MA^a, Hong SUI^a,b,c,
Lin HE^a,b, Xingang LI^a,b,c

^a School
of Chemical Engineering and Technology, Tianjin University, Tianjin 300072,
China.

^b Collaborative
Innovation Center of Chemical Science and Engineering(Tianjin), 300072, China.

^c
National Engineering Research Centre of Distillation Technology, Tianjin,
300072, China.

Different from the
traditional crude oil, the unconventional oil ores (e.g., oil shale, oil sands,
asphalt rocks, etc.) consist of heavy/extra-heavy oil, minerals and water. The
geological reserves of unconventional oils (tight oil, natural gas liquids,
kerogen oil, extra-heavy oil and bitumen) account for about 64% of total
petroleum reserves¹. It is
reported that the crude bitumen production in Alberta reached 2.45 million
barrels per day in 2016, and the production of crude bitumen in Alberta should
be sufficient to meet Canada¡¯s needs of crude oil for the next several
centuries². The Indonesian
asphalt rocks, with approximately 100 million tons of asphalt reserves, was
firstly reported in 1936 after the discovery of the Buton island³, which is located off the southeast
peninsula of Sulawesi in Indonesia. The Indonesian asphalt rocks, with bitumen
content up to 50 wt %, are known as oil-wetted ores
without the water film between bitumen and mineral solid surface. The currently
used commercial method for bitumen recovery from Athabasca oil sands is the hot
water based extraction (HWBE). However, this HWBE
process is limited to some extent during the industrial application due to some
environmental issues, and the HWBE process has a poor bitumen recovery with the
oil-wetted ores⁴. Solvent
extraction has been considered a promising process with high recovery rates and
can also be employed on various types of oil sands, most notably on oil-wetted
oil sands.

In this study, the solvent extraction process
has been used to recovery the bitumen from Indonesia asphalt rocks. Both the
bitumen recovery, particle sedimentation and the suspended particle flocculation
have been investigated. A multi-staged solvent extraction
process has been used to recovery the heavy hydrocarbons from Indonesian
asphalt rocks with four typical solvents (i.e., toluene, n-heptane, n-hexane,
and cyclohexane). Results show that although solvent type-dependent, the
solvent extraction gives an extremely high recovery (up to 98%) of heavy
hydrocarbons compared with that of HWBE process without water being involved. After
the extraction, a systematical particle sedimentation test has been conducted
in the non-aqueous phase. The equilibrium height of settled solids is found to be
higher in n-hexane and n-heptane systems than those in toluene and cyclohexane
systems at given conditions, which is mainly contributed to the higher bitumen
components (e.g., asphaltenes) attached on the solid surfaces. A mathematical
model has been proposed to describe the carbonate particle settling behaviors
for the interfaces in different solvent extraction systems. For the suspended particle
in the bitumen solution, different polymer flocculants
have been applied, resulting a flocculation rate up to 95%.

These findings provide the application of solvent
extraction in recovery the heavy hydrocarbons from Indonesian asphalt rocks. It
is believed that the solvent extraction process would be a promising method for
the recovery of unconventional oil from the ores.

References:

1.             International
Energy Agency. World Energy Outlook 2018;
2018.

2.             Alberta
Energy Regulator. ST98: 2017 Alberta¡¯s
Energy Reserves & Supply/Demand Outlook; 2017.

3.             Davidson
JW. The geology and prospectivity of Buton island, SE Sulawesi, Indonesia. In: Twentieth Annual Convention of the
Indonesian Petroleum Association. Jkarta, Indonesia; 1991.

4.             Masliyah
J, Zhou ZJ, Xu ZH, Czarnecki J, Hamza H. Understanding water-based bitumen
extraction from athabasca oil sands. Can.
J. Chem. Eng. 2004;82(4):628-654.