CONTROL AND SENSING SYSTEM BASED ON FUZZY LOGIC FOR DOMESTIC REFUSE INCINERATORS

In refuse incineration, controller design is a matter of trade-off between poorly defined control objectives under poorly defined conditions, in the sense that real time measurement of dioxin production is impossible and the quality of refuse feed to the incinerator is difficult to define, since its content is usually inhomogeneous and its calorific value not measured. The critical requirement for refuse incineration is clean and thorough thermal decomposition of refuse so that production of dioxin is minimized. In Hitachi Zosen Corporation, we have developed a control and sensing system for these incinerators based on fuzzy logic. In the sensor part of the system, the quality of combustion inside the furnace is evaluated by means of 3 parameters -the Combustion Center Point (CCP), the Refuse Mass Energy (RME) and the Air Balance in Furnace (ABF) -which are determined based on fuzzy logic from a range of measurements. In the control part of the system, control input such as the amount of air injection, refuse feed rate, etc., to the furnace are controlled using a fuzzy controller which use the current control input and the quality of combustion as input parameters. This sensing and control system has been implemented and tested in domestic refuse incinerators built by Hitachi Zosen Corporation.