Evaluation of Economics and Energy Saving Characteristics of Urban Waste Treatment and Utilization Systems

Abstract

This paper evaluates economics and energy saving characteristics of total systems which treat municipal refuse and utilize its contained energy. Investigated total systems are the following two systems: (1) System-A is composed of a municipal refuse incineration plant and a cogeneration system with a bleeder/condensate turbine power generation unit, and (2) System-B is composed of a pyrolysis furnace for treating the municipal refuse and a cogeneration system which is constructed by a combined cycle power generation unit using cleaned pyrolysis gas as its fuel gas. The followings were shown through a case study: (1) System-A is the better in economy and its energy saving characteristics is excellent, if it can be assumed that the total system is incorporated into a large district cooling and heating system (LDCHS) and that its maximum supply heat can all be used to supply base heat demand. (2) In case no LDCHS exists, the following results were obtained; (a) As for System-A, supplying both heat and electric energy is preferable from a comprehensive point of view instead of supplying only electric energy. (b) As for System-B, which has high power generation efficiency, supplying only electric energy is desirable instead of supplying heat energy as well. (c) Economics of System-B is better and energy saving characteristics is much better than System-A.