Page 185 - Process Equipment and Plant Design Principles and Practices by Subhabrata Ray Gargi Das

6.5 Evaporator accessories 183

Evaporator
accessories

Condensate
Condenser and removal
vacuum system system (pumps
and taps)

Vacuum system
Condenser Vent/ Catchall (vacuum pump
or ejector)

Surface Direct contact

Jet (wet) Countercurrent
condenser Barometric
(dry)
FIGURE 6.16
Evaporator accessories.

The most common type of direct contact condensers is the counter-current barometric condenser.
Here vapor is condensed while rising against a shower of cooling water,
and the condenser is located at an elevation allowing gravity discharge
of water from vacuum in the condenser through the barometric leg.
Barometric condenser
Such condensers are inexpensive and economical on water consump-
tion. They can usually be used to maintain a vacuum corresponding to a

saturated vapor temperature within 3 C of the water temperature
leaving the condenser. The ratio of water consumption to vapor condensed can be determined from
enthalpy balance.
Jet or wet condensers use high-velocity water jets both for condensation of vapor and also to force
noncondensable gases out of the tailpipe. This type of condenser is placed at
a lower elevation (below barometric height) and requires a pump to remove
the mixture of water and gases. Jet condensers consume more water than
Jet Condenser
common barometric type condenser and cannot be throttled conveniently to
conserve water at low evaporation rates.