Factors Determining the Element Behavior in Municipal Solid Waste Incinerators. 1. Field Studies

Abstract

This paper investigates the factors determining element behavior in municipal solid waste incinerators. The method is based primarily on field measurements in full-scale incinerators. Material flow analyses are carried out in an incinerator. The main focus is placed on the processes in the furnace. The following master variables determine element transfer behavior to the raw gas in the furnace: (i) occurrence and distribution of the elements in the input waste; (ii) temperature, redox conditions, and content of chlorine and of reaction partners other than oxygen and chlorine in the furnace bed; and (iii) residence time and mixing conditions in the furnace bed. Twenty-nine elements are divided into two groups with respect to their transfer behavior to the raw gas and to the bottom ash in the furnace. The results indicate that the elements Si, Fe, Co, Cr, Mn, Ni, P, Al, Ca, Mg, Na, Ba, Li, Ti, and K are transferred mainly to the raw gas by entrainment. Occurrence and distribution of these elements in the input waste determine primarily their transfer coefficients. Evaporation is the main transfer process for the remaining investigated elements to the raw gas. In addition to the occurrence and distribution of the elements in the input waste, physical and chemical conditions as well as kinetics are the main factors responsible for the different transfer behaviors between the elements F, Cu, Mo, Pb, Sn, Zn, Br, Sb, C, S, Cl, As, Cd, and Hg.