Overview of Pyrolysis, Thermal Gasification, and Liquefaction Processes in Japan

Abstract

The need ofor a better solid waste disposal system has stimulated a great deal of interest in the application of pyrolysis to solid wastes instead of the traditional incineration system in Japan. Since the Agency of Industrial Science and Technology, MITI had launched the national project on development of technology and system of resource recovery from refuse in 1973, more than a dozen processes of pyrolysis, thermal gasification and liquefaction (PTGL) are being developed at the national level, municipal level, and the level of private companies. On the other hand, the spread of the activated sludge method to treat sewage has created problems of sludge disposal. The incineration process has been increasingly adopted as the method ofor reducing the volume and residues. But it has been recently pointed out that incineration of sewage sludge causes air and water pollution and leaching of heavy metals (especially Cr/sup +6/ compounds) from ash, the same as in incineration of domestic refuse. To cope with this situation, the drying-pyrolysis process has been developed as the most feasible method f sludge treatment and disposal which minimizes the secondary pollution problems. The aim of this paper is to describe the present status of development and application,more » and evaluation of PTGL processes in Japan.« less