Environmental Engineering Reference
In-Depth Information
1-c)
2-c)
Fuel combustion heat
Sensible heat of exhaust
gas from thermal stage
media
1-d)
Sensible heat of pre-
heated air
1-b)
2-b)
Sensible heat of
upstream exhaust gas
Sensible heat of
exhaust gas
1-e)
Scale forming heat
2-a)
1-a)
Sensible heat of steel
at discharging side
Sensible heat of steel
at charging side
The steel to reheat
2-d)
2-e)
Heat loss by zone
cooling water
Heat radiation from
furnace body
FIGURE 5.29
Heat balance in a zone.
1. φ
CG
2. The temperatures set for each zone and combustion
3.
The heat radiation loss from the furnace and the overall heat transfer
coefficient for the loss by cooling water
4.
Combustion conditions (gas composition, air ratio, and atmospheric
temperature)
This simulator is applicable to semifinished steel in the form of slabs, round
billets, and billets and it requires the data input of 22 thermal properties of various
types of steel. The following data are necessary on the operational conditions related
to each form of steel:
1.
Steel material type
2.
Discharge temperature and the difference of the temperature
3.
Size of the steel, thickness, width, and length, and charging intervals
4.
Charging temperature and designated steel type
5.2.2
B
ASIC
F
UNCTIONS
OF
THE
S
IMULATOR
A heat balance model of a basic reheating furnace was constructed. The basic features
of the reheating furnace used for the present study are explained by using the example
of a continuous reheating furnace with regenerative heating exchangers. The con-
tinuous reheating furnace is divided into four zones: (1) noncombustion zone, (2)
preheating zone, (3) heating zone, and (4) soaking zone. In each zone, the heat
balance between heat input and output is obtained using calculation models. These
are models of the temperature inside the steel, of combustion based on fuel compo-
sition, of preheated air temperature based on a given thermal efficiency, and of the
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