A coal liquefaction pilot plant of the NEDOL process, supported by New Energy and Industrial Technology Development Organization (NEDO), was in successful operation for a total of 269 days at Kashima, Japan. The liquefaction section involved three bubble-column liquefaction reactors, 1m in diameter, connected in series, and processed 150 tons of coal per day. The hydrodynamics and thermal behavior of the reactors were investigated. The relations of yields and actual slurry residence time measured by the neutron absorption tracer technique were shown in the case of Tanitoharum coal.
The procedure for designing the 4m diameter reactors to process 2, 500 tons of coal per day, was developed based on the yields estimated by the reaction simulator validated by the data obtained on the pilot plant. The ratio of heavy oil fraction in recycled solvent was a determinant factor to maintain the stable operation. The design was also supported by the model study estimating the thermal behaviors, discussing the effect of mixing on the thermal efficiency.
