Method and apparatus for producing solid fuel

An apparatus comprising:

• (A) a mixer to mix porous coal with a mixed oil containing a heavy oil and a solvent oil to prepare a raw material slurry;
• (B) an evaporator connected to the mixer (A) and disposed on a downstream side of a flow of the raw material slurry with respect to the mixer (A), to heat the raw material slurry to promote dehydration of the porous coal while impregnating pores of the porous coal with the mixed oil to obtain a dehydrated slurry;
• (C) a solid-liquid separator connected to the evaporator (B) and disposed on a downstream side of a flow of the dehydrated slurry with respect to the evaporator (B), to separate an upgraded porous coal and the mixed oil from the dehydrated slurry;
• (D) a drying device to dry the upgraded porous coal to obtain a dried porous coal, comprising:
• (D-1) a dryer connected to the solid-liquid separator (C) and disposed on a downstream side of a flow of the upgraded porous coal with respect to the solid-liquid separator (C), to dry the upgraded porous coal with a carrier gas, the dryer (D-1) comprising:
• an inlet of the carrier gas;
• and an outlet of the carrier gas, the carrier gas at the outlet including a dust coal and a vaporized mixed oil;
• and
• (D-2) a gas cooler disposed between the outlet of the carrier gas and the inlet of the carrier gas, to cool the carrier gas to condense the vaporized mixed oil in the carrier gas, while capturing the dust coal in the carrier gas by atomization of the condensed mixed oil, thereby recovering the mixed oil which includes the dust coal;
• (E) a first return path disposed between the solid-liquid separator (C) and the mixer (A), to return the mixed oil separated and recovered by the solid-liquid separator (C) to the mixer (A);
• and
• (F) a second return path disposed between the solid-liquid separator (C) and the drying device (D), to return the mixed oil recovered by the drying device (D) to the solid-liquid separator (C).