Spray-type Deaerators
Stork Thermeq B.V.
Spray-type Deaerators
General A proper designed steam device, taking into account the
hydro-dynamics in the water tank, will result in good con-
Many decades of experience have given the Stork spray- tact between water and steam, allowing the oxygen to
type deaerator a unique place in the deaerating industry. move from the water to the steam in accordance with
The patented design has been used world-wide in power Henry’s law.
plants and industrial installations to the full satisfaction of
our customers. Continuous improvements and flexibility 1) Required temperature difference for O2 < 10 ppb
make it possible to provide highly competitive solutions 35
for power plant design.
∆T inlet/outlet (0C)
20
25
20
Operation principle
15
10
The operation of the deaerator is based on physical
5
deaeration which takes place in two steps:
0
Pre-deaeration in which water is sprayed in a part of the 0 2 4 6 8 10
steam space (area 1) ; O2-content at inlet (mg/l)
Final-deaeration in the water tank where steam is
brought in close contact with the water to be deaerated 2) O2 concentrations in saturated demi-water
(area 2). 16
O2 concentration (mg/l) 14
The pre-deaeration (area 1) is achieved by the Stork
12
spraying device. Under all kind of operating conditions,
10
the sprayer assures heating up of the condensate to sat-
8
uration temperature and a very large area for mass trans-
6
fer. As the solubility of oxygen in water at saturation con-
4
ditions is practically zero, oxygen transfers from the
water droplets to the surrounding steam. As the steam 2
condensates on the water, the concentration of oxygen in 0
0 20 40 60 80 100
the direct vicinity of the sprayer is increased making it
Temperature (0C)
possible to vent a small amount of steam with a relatively
high oxygen concentration.
Final deaeration (area 2) in the water tank is achieved by
injection of steam in the water tank. Depending on the
conditions steam, pressurized hot water, steam/water
mixture can be used for deaeration.
Pre deaeration Area 1
Final deaeration Area 2
Spray-type Deaerators
Applications 1
Conventional power plants
The Stork spray-type deaerator has been developed for
application in conventional power plants.
A principal scheme is given in figure 1.
Co-generation power plants
Based on the principles of deaerators for conventional
power plants we developed special Stork spray-type
deaerators for/and connections to Heat Recovery Steam
Generator (HRSG) installations.
The Stork spray-type deaerator provides a high degree of
flexibility concerning the place in the cold end of a HRSG.
Application of a Stork spray-type deaerator gives the sys- 2
tem designer several options for the connection to the
system and the choise of the most suitable deaerating
medium, or media. The Stork spray-type deaerator is
especially suitable for this kind of application compared to
tray-type deaerators. This because of its ability to operate
with steam/water mixtures, its greater flexibility with
respect to fast load changes, sliding pressure operation
and wider operating ranges.
Depending on the client preferences and/or over-all effi-
ciency considerations, the Stork spray-type deaerator
can be installed in various ways in the boiler system. The
principal difference between the various possibilities is
set by the choice of deaerating medium, such as:
- LP steam
- Pressurized hot water
- Steam/water mixtures 3
Some possibilities are best illustrated by the figures on
the right side of this page. The figures 2 and 3 show two
basic configurations in the cold end of a HRSG.
Figure 2 Economiser hot water deaeration (vacuum)
Figure 3 Evaporator bundle, natural or forced circulation
Typical operating ranges of the Stork spray-type deareator
Operating pressure Temperature
ranges (bara) difference* ( 0C )
min. max.
0.2 < Po < 0.5 3 30
0.5 < Po < 1 5 50
1. Boiler 11. Gasturbine
Po > 1 8 >100 2. HP-steam turbine 12. Generator
3. LP-steam turbine 13. Heat Recovery Steam
* Temperature difference between incoming condensate 4. Generator Generator
and feed water outlet temperature. 5. Condenser 14. Hot-water control valve
6. Condensate pump 15. Deaerator (vacuum)
All the above mentioned values are typical values. 7. LP-preheater 16. LP/HP-drums
Please contact Stork Thermeq if you have more specific 8. Deaerator (conventional) 17. Evaporator bundle for
questions about your particular situation or visit our 9. Boiler feed water pump Deaerator
website. 10. HP-preheater 18. Deaerator/LP-drum
Spray-type Deaerators
Features Advantages
- Reduction of oxygen concentrations to levels below 5 Lower Total Cost of Ownership, due to:
ppb over wide operating ranges (10 to 110%); - Simple, robust design resulting in minimal maintenance;
- High reliability/availability; - Steam consumption savings by a very small vent flow,
- Single shell design; no vent condenser necessary
- Deaerated water available as soon as the deaerator is
pressurised; Single shell design, resulting in:
- Possible deaerating media: (superheated) steam, - Compact construction with low overall height;
steam/water mixtures, hot-water or combinations here of; - Lower insulation and piping costs compared to other
- Sliding pressure operation possible, from vacuum (0.2 designs;
bara) to several bar over pressure; - Simple erection;
- Robust design, allowing very rapid load changes; - High earthquake resistance;
- Low vent losses, 10 to 70 kg/s depending on amount of
incoming oxygen;
- Capacity range at the outlet from 10 to 6000 ton/hour,
special models possible.
Stork Thermeq B.V.
P.O. Box 33, 7550 AA Hengelo, The Netherlands
Visiting address:
Langelermaatweg 12, 7553 JD Hengelo, The Netherlands
Tel.: +31 74 240 1724
Fax: +31 74 242 4790
e-mail: info.thermeq@stork.com
Website: www.thermeq.nl
