Potential Applications of High Temperature Air Combustion Technology to Other Systems - High Temperature Air Combustion: From Energy Conservation to Pollution Reduction - page 350

the solid w astes. The process of making RDF involves sorting the waste, followed

by size reduction, pulverization, drying, particle size conditioning, and transforma-
tion to size and shape. In Japan, the term RDF is more frequently used than WDF.
These two terms refer to the same thing, and there are no clear definitions or standards
for them. It is expected that the relevant standards are likely to be established in the
near future in Japan. However in the United States, the ASTM (American Society
for Testing and Materials) classifies the RDF products in various categories;

Table 6.3 . The RDF-5 shown in this table is equivalent to the RDF generally referred
to in Japan with a diameter of several tens of millimeters. The RDF can also be
gasified to form medium to high calorific value gas using high temperature air/steam
or oxygen enriched high temperature air/steam. The advantage here is clean gas with
no particulates or fly ash.

see

7

6.2.1.2 Applied Technology for RDF

Formerly, municipal waste was simply incinerated for disposal. The energy was not
actively utilized for power generation purposes or in heat utilization applications
other than the incineration facility itself. Today, municipal waste combustion tech-
nologies are being further developed with recycled material with a goal approaching
zero emission and using the energy evolved. The following section provides a
comparison of characteristics between the RDF combustion technology and munic-
ipal waste incineration technology.

6.2.1.3 Changes in the Calorific Value of Municipal Wastes

Figure 6.8 shows the energy balance of RDF with the energy consumption required
for the production of RDF (taken as the base level). 8,9 The manufacturing process

TABLE 6.3
Classification of Refuse Derived Fuel (RDF)

Classification Description Type

RDF-1 Municipal waste to be converted to fuel excluding

bulky waste

—

RDF-2 Mixed municipal waste, 95% of which has been

filtered through 6-in mesh. Iron components are
removed or retained depending on the needs

Fluff RDF

RDF-3 Municipal waste, 95% of which has been filtered

through 2-in mesh. Glass and inorganic substances
are removed

RDF-4 Combustible powdered waste, 95% of which has been

filtered through a 2-mm (#10) mesh screen

Powder RDF

RDF-5 Combustible waste formed into pellets, cubes, or

briquettes using compression method

Densified RDF

RDF-6 Combustible waste processed into liquid fuel —

RDF-7 Combustible waste processed into gaseous fuel —