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.
To evaluate the recycle of Ny6, the energy consumption for the production of virgin Ny6 resin was compared with that of recycled Ny6 resin by LCI analysis. As a large amount of ammonium sulfate is produced as a by-product with virgin Ny6 from the same process, consumed energy and airborne emissions must be allocated to both products. The calculation result showed that the energy consumption for the production of virgin Ny6 was 170.7MJ/kg by the allocation method based on their prices. It was almost the same as the energy consumption of virgin Ny6 allocating all consumed energy to it, which was 177.8MJ/kg. Meanwhile, the energy consumption for the production of recycling Ny6 resin was 77.0MJ/kg. It was thought that the recycle of Ny6 had an advantage compared with virgin Ny6 from the viewpoint of the energy consumption. It should be noted that this analysis did not include the energy consumption to recover Ny6 textile and the weight loss at the degradation process of recovered Ny6.
This study was conducted to clarify the capabilities of introducing a district cooling and heating system using the waste heat from the power generated by garbage incineration into the urban energy system. This system was compared with an independent air conditioning system and a dis-trict cooling and heating system using city gas. The results show the use of garbage generated waste heat to be highest in equipment costs and lowest in energy consumption among the three above-mentioned systems. The total costs of equipment plus energy vary with the volume of heat demand and the distances from the heat source to the demand sites. Consequently in the district cooling and heating system, the substitution of waste heat from the power generated by garbage incineration for city gas can reduce CO2 emissions at the cost of 15, 000yen/ton-CO2. This is dependent upon the distances between heat source and heat demand site being from 2-8km, with daily heat demands being 500-5, 000GJ/d for the respective distances from heat sources.