NIRE Annual Report		1998

Objectives

The separation of phenols from coal liquid is expected to reduce coal liquefaction cost because of a large profit by marketing recovered phenols as chemicals, and the reduction of hydrogen consumption at the upgrading stage of coal liquid. A methanol-mediated extraction method was developed for the purpose, which feature is to add methanol (MeOH) and water (H₂O) one by one. The advantages are immediate extraction at normal temperature and pressure, and the use of only MeOH and H₂O as extraction solvents in closed system. We have been studied the behavior of phenols on the extraction, and a concept of the process.

Results

The extraction yield depended on the ratios of added MeOH and H₂O based on coal liquid. It was more than 90% on a MeOH rich condition, and decreased with increase in H₂O on the condition of MeOH/ H₂O > 1. A small amount of neutral oil, which is a contaminant of phenol products, was also extracted. Based on these results, the optimum operation condition was established as MeOH/H₂O = 1. The extraction yield is expected more than 70% using the same amount of coal liquid, MeOH and H₂O. Applying this method to the naphtha fraction of Tanitoharum coal liquid containing about 17wt% phenols, the extraction yields were about 75%. These results indicate that about 13wt% of naphtha fraction can sell as crude phenols, and hydrogen consumption at upgrading stage reduces to about a quarter, suggesting the profits from phenols and the reducing the hydrogen cost contribute to the cost reduction of coal liquefaction.

We have finished to design the overall process flow diagram for the feasibility study.

Papers

1)	Kodera,Y., Ukegawa, K., Mito, Y., Komoto, M., Ishikawa, E., Nakayama, T., Fuel, 70, 765, 1991.
2)	Kodera,Y., Ukegawa, K., Mito, Y., Ma, X., Fuel, 72, 57, 1993.
3)	Sato,S., Matsumura,A., Kodera,Y., Saito,I., Ukegawa,K., Nagano,M., J. Jpn. Inst. Energy, 76, 1054, 1997.

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