Laboratory of Solid Waste Disposal Engineering, Faculty of Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo 060 8628, Japan.
Waste Manag. 2012 Mar;32(3):410-6. doi: 10.1016/j.wasman.2011.10.006. Epub 2011 Nov 21.
Hydrothermal treatments using subcritical water (HTSW) such as that at 234°C and 3MPa (LT condition) and 295°C and 8MPa (HT condition) were investigated to recover solid fuel from municipal solid waste (MSW). Printing paper, dog food (DF), wooden chopsticks, and mixed plastic film and sheets of polyethylene, polypropylene, and polystyrene were prepared as model MSW components, in which polyvinylchloride (PVC) powder and sodium chloride were used to simulate Cl sources. While more than 75% of carbon in paper, DF, and wood was recovered as char under both LT and HT conditions, plastics did not degrade under either LT or HT conditions. The heating value (HV) of obtained char was 13,886-27,544 kJ/kg and was comparable to that of brown coal and lignite. Higher formation of fixed carbon and greater oxygen dissociation during HTSW were thought to improve the HV of char. Cl atoms added as PVC powder and sodium chloride to raw material remained in char after HTSW. However, most Cl originating from PVC was found to converse into soluble Cl compounds during HTSW under the HT condition and could be removed by washing. From these results, the merit of HTSW as a method of recovering solid fuel from MSW is considered to produce char with minimal carbon loss without a drying process prior to HTSW. In addition, Cl originating from PVC decomposes into soluble Cl compound under the HT condition. The combination of HTSW under the HT condition and char washing might improve the quality of char as alternative fuel.
采用亚临界水（HTSW）的水热处理，例如 234°C 和 3MPa（LT 条件）和 295°C 和 8MPa（HT 条件），被用于从城市固体废物（MSW）中回收固体燃料。打印纸、狗食（DF）、木筷以及混合塑料薄膜和聚乙烯、聚丙烯和聚苯乙烯片被制备为模型 MSW 成分，其中聚氯乙烯（PVC）粉末和氯化钠被用于模拟 Cl 源。虽然在 LT 和 HT 条件下，纸张、DF 和木材中的碳超过 75%都以炭的形式回收，但塑料在 LT 或 HT 条件下都不会降解。获得的炭的发热值（HV）为 13886-27544 kJ/kg，与褐煤和烟煤相当。在 HTSW 中，较高的固定碳形成和更大的氧离解被认为提高了炭的 HV。作为 PVC 粉末和氯化钠添加到原料中的 Cl 原子在 HTSW 后仍留在炭中。然而，在 HT 条件下，大多数源自 PVC 的 Cl 被发现在 HTSW 过程中转化为可溶的 Cl 化合物，可以通过洗涤去除。从这些结果可以看出，HTSW 作为从 MSW 中回收固体燃料的方法具有优势，可以在不进行 HTSW 前干燥过程的情况下，以最小的碳损失生产炭。此外，在 HT 条件下，源自 PVC 的 Cl 分解为可溶的 Cl 化合物。HTSW 与炭洗涤的结合可能会提高炭作为替代燃料的质量。
