Civil Engineering Reference
In-Depth Information
Fig. 6.2
Enthalpy entropy diagram for water (Mollier diagram—English units)
Industrial boilers can be classified as either watertube or firetube depending on
the position of the hot combustion gases in relation to the fluid being heated (water,
oil). Oil can be used as the heating medium both to carry thermal energy directly to
the end users and to produce steam by means of a heat exchanger acting as an
evaporator inside or outside the boiler plant.
The so-called unfired boilers such as heat recovery boilers and electric or
electrode boilers, can also be installed, depending on technical and economic
factors, in order to transfer thermal energy to end users without combustion inside
the boiler itself.
Boilers which recover latent heat from the water vapor in stack flue gases are
called condensing boilers (see also Sect.
6.8
).
