During thermal vapour recompression, vapour from a boiling chamber
is recompressed to the higher pressure of a heating chamber according
to the heat pump principle; i.e. energy is added to the vapour. The saturated
steam temperature corresponding to the heating chamber pressure
is consequently higher, enabling the vapour to be reused for heating.
For this purpose, steam jet vapour recompressors are used. They operate
according to the jet pump principle. They have no moving parts,
ensuring a simple and effective design that provides the highest possible
operational reliability.
The use of a thermal vapour recompressor has the same steam/energy
saving effect as an additional evaporation effect.
A product to be
evaporated
B residual vapour
C concentrate
D motive steam
E heating steam
condensate
F vapour condensate
V heat loss
Heat flow diagram of a
double-effect, directly heated
evaporator
4
Acertain quantity of live steam, the so-called motive
steam, is required for the operation of a thermal vapour
recompressor. This motive steam quantity must be transferred
to the next effect or to the condenser as surplus
residual vapour. The surplus energy contained in the residual
vapour approximately corresponds to the amount
of energy supplied in the motive steam.