1 October 1997
BASICS OF INCINERATION
3-1. DEFINITION AND DESCRIPTION OF INCINERATION PROCESS.
a. Definition. Incineration is a controlled combustion process for reducing solid, liquid, or
gaseous combustible wastes primarily to carbon dioxide, water vapor, other gases, and a relatively
small, noncombustible residue that can be further processed or land-filled in an environmentally
b. Description. The incineration of solid waste involves a sequence of steps in the primary
process, which includes drying, volatilization, combustion of fixed carbon, and burnout of char of the
solids, which is followed by a secondary process, the combustion of the vapors, gases, and
particulates driven off during the primary process.
CLASSIFICATION AND CHARACTERIZATION OF WASTE.
a. Waste Classification. Four types of waste have been identified in this manual. The Basic
properties and descriptions of these four types are presented in Table 3-1.
b. Waste Characterization. Detailed combustion characteristics are needed for the calculation
of heat balances for the incinerator. For design purposes, the most important characteristics are
the higher heating value, moisture content, and percent of inert material in the waste.
(1) Maintaining minimum moisture is important as the energy required to dry the waste
reduces the energy available to volatize vapors and provide the necessary gas temperatures to
complete the destruction of the unburned gases, vapors, and particulates.
(2) Plastic wastes typically have a high specific-heating value (i.e., Btu/lb). The composite-
waste Btu content is therefore sensitive to the percent of plastics and other dry, high-Btu material
(e.g., cardboard, paper, etc.) in the incinerator feedstock. Tables 3-2 and 3-3 provide combustion
data on some materials in domestic and commercial wastes. Table 3-4 shows the nominal
composition of discards in municipal waste (household waste).
(3) The percentages of components in the waste which is to be combusted must be
determined on the basis of a waste characterization analysis appendix B contains thermodynamic
data and examples of combustion analysis.
3-3. HEATING VALUE OF WASTES AND FUELS.
a. Heating Value. The heating value for combustible materials may be presented in many
ways. Table 3-3 lists the "as-fired" heating values generally assigned to different types of waste,
some chemicals, and major constituents in municipal-type, and industrial-type, wastes. Table 3-5
lists the chemical analyses of some municipal, residential, and commercial wastes and indicates the
higher heating values of the combined waste stream for as-received, moisture-free, and ash-free
material. Table 3-6 lists the proximate analysis of 30 different components in municipal and