THE PRINCIPLE OF RECYCLING AND OPTIMIZATION
AS APPLIED TO BATCH-OPERATED THERMAL PROCESSING PLANTS
N. A. Tyutin
Translated from Ogneupory i Tekhnicheskaya Keramika, No. 4, pp. 46 – 49, April, 2002.
The efficiency of continuous and batch-operated thermal processing is analyzed in terms of fuel rate and
heat-treatment process control. The principle of recycling of the working medium is proposed for optimization
of batched-operated plants. The recycling ratio is proposed as an optimization criterion.
In modern technology, ceramic materials are thermally
processed using continuous or batch-operated thermal pro-
cessing plants (TPP). Continuous plants are employed for
large-scale production, and batch plants — for small-scale or
serial production of ceramic components.
The main element of any TPP is a reactor (or reactors) in
which the product is processed . The working medium for
reactors is mainly the combustion products of hydrocarbon
fuel, their air mixtures, atmospheric air, or gas mixture of
are classified as open systems.
A product can be thermally treated using a single-stage
or a two-stage process. In the single-stage process, for exam
ple drying, the product is just heated at specified heating
rates and isothermal holding times.
Any thermal process carried out in the TPP reactor is
characterized by a set of parameters that in fact determine the
selected heating regime. An important characteristic of the
heating regime is the temperature regime of the reactor
which is determined as a functional dependence of the work
ing medium of the reactor on the processing time.
The temperature regime of the reactor is set with allow
ance for the conditions under which the given ceramic prod
uct should be heat-treated. The temperature at which the
product is processed is usually described by a continuous
curve plotted as a function of the processing time; graphi
cally, it can be represented by a parabola or by a Gaussian
In a TPP, the temperature regime of the product and, cor-
respondingly, the temperature regime of the reactor are com-
monly expressed by a simple linear or piecewise linear func-
tion for a single-stage process (Fig. 1) and by a piecewise lin-
ear function for a two-stage process (Figs. 2 and 3). For the
single-stage process, both regimes are continuous functions.
For the two-stage process, the temperature regime of the
product is represented by a continuous function, and the tem-
perature regime of the reactor — by a discontinuous function
with a discontinuity point at the boundary demarcating two
neighboring stages of the heating process.
Refractories and Industrial Ceramics Vol. 43, Nos.3–4, 2002
1083-4877/02/0304-0157$27.00 © 2002 Plenum Publishing Corporation
Eastern Institute of Refractories Research and Production Associ
ation Joint-Stock Co., Ekaterinburg, Russia.
Fig. 1. Temperature regimes of the reactor (1 ) and the product (2 )
represented as linear (a) and piecewise linear (b ) functions for the
single-stage process of continuous and batch TPP: T ) temperature,
t) time, and DT
) temperature stress.