CHOICE AND SUBSTANTIATION OF FURNACE CONSTRUCTION
FOR HEAT TREATMENT OF MOULDED FIBER OBJECTS
A. V. Matyukhina,
I. D. Kashcheev,
and V. I. Matyukhin
Translated from Novye Ogneupory, No. 5 pp. 48 – 52, May 2009.
Original article submitted July 28, 2008.
On the basis of analyzing furnace thermal and gas-dynamic operation for polymerization of mineral wool ob
jects advantages are demonstrated for using a gas movement circulation scheme. The required structural
changes for furnace working space operation are substantiated for obtaining high technical and economic indi
ces from data for material and thermal balances.
Keywords: mineral wool mat, polymerization furnace, gas stream filtration rate, device efficiency, material
In order to reduce heat losses in industry and civil con-
struction there is often use of molded fiber objects based on
natural and slag compositions using organic and inorganic
binders. In order to provide their specific strength and elastic
properties prior heat treatment is necessary.
Engineering limitations for heating parameters for
molded objects (temperature, heating rate, heat carrier filtra-
tion rate, gas atmosphere composition) suggest the choice of
furnace for performing this stage using a chamber regime.
Depending on the required unit productivity it is possible to
use heating equipment of the chamber or throughput type.
Within them at relatively low temperatures (up to
200 – 300°C) there is drying and strengthening of the min
eral-wool mat containing an aqueous solution of organic
binder in an amount of 2 – 3% for light product and up to
50 – 55% for heavy product. Within the unit there is also an
assembly for preparing the original moulded objects, 1 – 4
heating chambers, a cooling chamber, and a unit for prepar
ing finished objects.
Heat treatment of the untreated layer is accomplished in
a polymerization furnace successively in stages of drying,
polymerization (polycondensation), low-temperature firing
and cooling. By alternating the movement direction for hot
gases in successively installed heating chambers in a blow
ing-suction regime the total heat treatment time of objects
and molding them forming their quality varies. Preparation
of the original flow of heat carrier in a furnace is produced in
separate furnaces on burning liquid or gaseous fuel followed
by dilution of the combustion products with cold air from the
atmosphere or a gas-recirculator from the heating chamber. It
is also possible to use heat carrier from other high-tempera-
ture firing or melting units. Practice of producing heat insula-
tion materials shows that its technical and economic indices
and the finished product quality depend to a considerable ex-
tent of organization of the heating and gas-dynamic opera-
tion both for individual heating chambers and for the poly-
merization furnace as a whole.
Low-temperature heating conditions for material in a re-
gime of cross movement of heat carrier governs the convec
tive nature of heat exchange with heating gas whose intensity
depends on temperature level and the movement velocity of
gas atmosphere in the layer. During heat treatment of min
eral-wool objects with organic binder they are strengthened,
and this is accompanied by a small release of heat in the
range 80 – 120°C and absorption of it at 140 – 270°C. The
heat losses that arise are concealed due to burning of an addi
tional amount of fuel in a furnace. The engineering require
ments for firing heat insulation objects based on an organic
binder limit the level of maximum heat treatment tempera
ture to not above 300°C. Therefore the main factor governing
furnace productivity is the rate of gas stream filtration.
Realization of the required thermal and temperature con
ditions for heating molded objects is most effectively
achieved with a crossover scheme for material and heat car
rier movement. Here conditions are provided for flexible
control of the heating regime in an individual heating cham
ber due to variation of the filtration rate for gases, their tem
perature and gas stream distribution throughout the volume
of a chamber.
Refractories and Industrial Ceramics Vol. 50, No. 3, 2009
1083-4877/09/5003-0208 © 2009 Springer Science+Business Media, Inc.
GOUVPO UGTU-UPI, Ekaterinburg, Russia.