Results of Investigations on the Current State of Japanese Industrial Furnaces - High Temperature Air Combustion: From Energy Conservation to Pollution Reduction - page 362

TABLE A.2
Scope of Investigation

Contents Details Notes

1. Type of

industry

(1)
(2)

Chemical industry
Petroleum and coal
products manufacturing
industry
Ceramics and soil
products manufacturing
industry
Iron and steel industry
Non-ferrous and metals
manufacturing industry
Metals products
manufacturing industry

(7) General machinery

instrument
manufacturing industry
Electric instrument
manufacturing industry
Instrument for
transportation
manufacturing industry
Precision instrument
manufacturing industry

Iron and steel
industries:
including
casting and
forging
industries

:
10 industries,
listed in the
right column,
in mining and
manufacturing
industries
according to
Japan
Standard
Industry
Classification

(8)

(3)

(9)

(4)
(5)

(10)

(6)

2. Type of furnace : (1)

(2)
(3)
(4)
(5)

Blast furnace
Steel melting furnaces
Arc furnaces
Steel induction furnace
Steel vacuum melting
furnaces
Nonferrous and metals
melting furnace
Nonferrous and metals
induction furnace
Nonferrous and metals
vacuum melting furnace
Metals soaking furnace

(11) Metals heat treatment

furnace
Surface heat treatment
furnace
Surface treatment
furnace
Atmosphere gas
denaturing furnace
Metals sintering,
roasting furnace
Ceramics baking furnace
Ceramics melting
furnace

Excluding
incinerators 19 types of

furnaces,
listed in the
right column,
based on Japan
Standard
Products
Classification

(12)

(13)

(6) (14)

(7) (15)

(8) (16)

(17)

(9)

(10) Metals heating furnace (18) Chemical industry

furnace

(19) Drying furnaces

3. Facilities scale (1) Combustion furnaces: facilities over 582 kW (2.1 GJ/h)

(2) Electric furnaces: facilities over 50 kVA

of small furnaces with low heating capacities showed fluctuation, because these
small furnaces treat many kinds of materials. They operate in different conditions
and are therefore not stable. A summary of the above-mentioned analysis results
is shown in Table A.4 . The heat efficiencies of continuous furnaces are 52 to 55%
for large scale, 37 to 45% for middle scale, and 27 to 38% for small scale. In
contrast, the heat efficiencies of batch furnaces are at most 26 to 42% for large
scale and 10 to 34% for middle and small scale, values that are generally much
lower than expected.