ABSTRACT
The third chapter analyzes the current global situation of waste-to-energy (WtE) technologies, combustion processes, gasification, plasma gasification, and pyrolysis. The emphasis is mainly on the combustion process, especially that using moving grates, since it is the dominant technology in the majority of existing WtE plants worldwide. The first part of the chapter describes the combustion process–based WtE plant (with images of the relevant process flow diagrams and equipment). The main elements that are presented in depth are the bunker, control room, combustion chamber (including types of moving grates, rotary kiln, and fluidized bed), boiler, steam turbine/generator, condensers, district heating, district cooling, electrical system, bottom ash, state-of-the-art air pollution control systems (different flue-gas cleaning technologies/scrubbers, SNCR/SCR, fly-ash treatment via stabilization or solidification, etc.), and stack. Many photographs and illustrations of the parts of a combustion-based WtE plant are included. Finally, the R1 mathematical formula related to new high electrical efficiency WtE plants in Europe is analyzed (according to EU Directive 2008/98), in order to determine when a waste combustion installation is considered an energy recovery operation. The second part of the chapter describes alternative thermal treatment (ATT) technologies: pyrolysis, gasification, and plasma gasification, with accompanying photographs, tables of technical data, flow charts from different suppliers, and case studies from technical visits made by the author to a pyrolysis plant in India and a plasma gasification pilot plant in South Korea.
