PRODUCTION AND EQUIPMENT
RECONSTRUCTION OF A SMALL TUNNEL FURNACE
FOR FIRING REFRACTORY PRODUCTS
R. A. Pilipenko,
A. V. Pilipenko,
D. M. Logvinenko,
F. G. Taukchi,
A. I. Novikov,
V. M. Zubashchenko,
and D. A. Timoshenko
Translated from Novye Ogneupory, No. 3, pp. 101 – 104, March, 2014.
Original article submitted October 7, 2013.
A tunnel furnace which is being used to fire heat-insulating and refractory products internally recirculates
gases between the stacks of the products inside the furnace. The gases’ movement is due to the kinetic energy
imparted by high-speed jets of the combustion products. The jets are formed by high-speed GNB-80 burners
designed by the Gas Institute of the Ukrainian National Academy of Sciences. Thanks to the faster and more
uniform heating of the products, the protective muffles that were previously installed around the stacks have
been dismantled, the productivity of the furnace has increased 25 – 67%, and unit fuel consumption has de-
creased 15 – 25%.
Keywords: refractories, firing, uniformity of heating, high-speed burners, recirculation of gases.
The tunnel furnace at the ZAO “Teplokhimmontazh” (in
Staryi Oskol) was placed in service in 2002 and is designed
to fire heat-insulating, refractory, and high-refractory gen-
eral-use products with an apparent density of 0.5 – 1.3 g/cm
and complex shaped refractory products with an apparent
density of 2.0 – 2.5 g/cm
. The shaped products are used in
different types of high-temperature equipment. The working
space of the furnace is 24.2 m long and 928 mm wide. The
height reckoned along the side wall up to the keystone of the
arched roof is also 928 mm. The products are charged in the
form of stacks, with each stack being transported into the fur
nace on a cart 1100 mm long and 850 mm wide. The fuel for
the furnace is natural gas. The furnace’s temperature regime
is variable, depending on the type of product being fired.
Before the reconstruction was begun, 20 dual-pass
1GTP-25-15-0.5 burners were installed in the side walls of
the firing zone. Ten burners were installed on each side of the
furnace and were spaced 550 mm apart. The design of the
burners allows the gas nozzle to be repositioned along the
burner’s axis in order to control the length and diameter of
the flame. When the gas nozzle projects outside the burner,
the mixture of gas and air forms a long flame as it passes
through the central opening in the tip. When the nozzle is re-
tracted from that position, the flame which is formed is short.
The flame is shortened by having the mixture swirl about the
interior of the tip and be discharged perpendicular to the
burner axis. However, this increases the diameter of the
flame and lowers its velocity. The position of the nozzle is
regulated manually. The short distance between the charge
and the side walls of the furnace and the close proximity of
the carts to one another makes it impossible to avoid having
the flame impinge directly on the surface of the products be
ing fired. Thus, the products were protected from direct con
tact with the flame by the installation of a muffle with a
200-mm-thick wall about the perimeter of the charge
(Fig. 1). However, even the presence of the muffle has not al
ways made it possible to provide for uniform heating of the
products: the difference in the temperatures of the lateral sur
faces of the charge has ranged from 5 to 20°C, and the bot
tom courses of the charge are not fired at all.
In connection with the need to increase the productivity
of the furnace, it was decided to dismantle the muffle, in
crease the capacity of the carts by a corresponding amount,
and replace the heavily worn gas equipment of the furnace so
as to provide for rapid, uniform heating of the charge and re
duce unit fuel consumption. To attain a high degree of uni
Refractories and Industrial Ceramics Vol. 55, No. 2, July, 2014
1083-4877/14/05502-0093 © 2014 Springer Science+Business Media New York
Gas Institute of the Ukrainian National Academy of Sciences,
ChP “Task,” Kiev, Ukraine.
ZAO “PKF ‘NK,’” Staryi Oskol, Belgograd Oblast, Russia.