INCINERATION VERSUS GASIFICATION: A COMPARISON IN WASTE TO ENERGY PLANTS

摘要

Waste thermodestruction is a consolidated technology with worldwide applications with obvious advantages; nevertheless, it encounters problems not very easy to solve, such as those related to gas cleaning and to more and more restricting standards for emission control. One among its most important aspects is the possibility of heat recovery with production of valuable energy such as electric energy. Owing to this solution the costs of waste disposal are kept low and a contribution is given to solve the energetic problem. New plants and process solutions are therefore proposed to reduce costs, to improve the environment impact, and to increase the energetic recovery. Its employment is however subordinated to the possibility of achieving advantages with reference to well consolidated traditional technologies, at least with reference to some of the above mentioned aspects (costs, environmental impact, etc.).A new technology, at least as far as its application to waste disposal (mainly municipal waste) is concerned, is represented by gasification. It becomes therefore interesting to establish a comparison between this "new technology" and the traditional one, keeping specifically in mind the above mentioned aspects. This comparison does not appear however very simple, being available for the traditional technology a wide and plentiful documentation, well field experimented, while for gasification only few documented experiments can be found, often difficult to be related to a common evaluation factor. It seams however convenient to try anyway to analyse the problem, also with the purpose to help the development of new technologies.The present paper describes first the state of the art of the traditional technology in the thermodestruction field, to define a comparison basis. Then a general discussion is given for the gasification technology, emphasizing different possible solutions to allow for a quantitative evaluation. At last the various aspects of the problem (related to plant, environment, energy, economics, etc.) are specifically compared with the purpose to find elements allowing for a quantitative evaluation or to emphasize parameters useful for a final choice.