Spray Cooling for Performance Enhancement of Air-Cooled Condensers by agu19334

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									     Spray Cooling for
Performance Enhancement of
   Air-Cooled Condensers
           J.S. Maulbetsch
            M. N. DiFilippo
             K. D. Zammit

   EPRI Advanced Cooling Workshop
       Charlotte, North Carolina
           August 9, 2008
Alternative
Solutions

 Hybrid wet-dry systems
  – Commonly used for plume abatement
  – Several design options

 Spray-enhanced dry cooling
  – Technology adaptation from
    gas turbine units
Spray-Enhanced
Dry Cooling

In gas turbines, inlet air
cooling racks used to
enhance efficiency
 – Pre-cooling spray nozzles
   introduce fine mist

In dry cooling systems,
approach could be applied
to pre-cool inlet air
 – Reduce capacity loss
 – Water use intermittent; rate
   ~25% full wet cooling
Spray-Enhanced
Dry Cooling

Without pre-cooling, ambient
T increase from ~55º to 90ºF
reduces capacity
 – For 235-MW unit, lose 10 to
   12 MW (~5%)

If air pre-cooled to 70%
relative humidity, capacity
loss reduced
 – For 235-MW unit, lose only
   3 to 5 MW
Chinese Camp
ACC at Chinese
Camp
Sprays in
operation
Mist entering fan
Spray
Enhancement
Spray Enhancement
Test Setup
Hot Day
Performance
                                   Average DB Temperature Profiles
                                       Crockett Single-Cell Spray Testing


                       100

                        95
   DB Temperature, F




                        90

                        85                                                       Deck DB

                        80                                                       Fan Outlet DB
                                                                                 B Exch DB
                        75
                                                                                 Glycol
                        70                                                       Deck WB
                                                                                 Fan Oultlet WB
                        65

                        60
                       12:00 PM   1:00 PM   2:00 PM    3:00 PM    4:00 PM   5:00 PM
Maximum Cooling
Effect
                                          Maximum Cooling Effect for Cell B Airflow

                                 10 gpm         15 gpm        20 gom        25 gpm        5 gpm

                            18
                            16
    Cooling Effect, deg F




                            14
                            12
                            10
                            8
                            6
                            4
                            2
                            0
                                 0          5            10            15            20           25

                                                Wet Bulb Depression, deg F
Cooling Effect
Results
                                         Cooling Effect vs. Wet Bulb Depression

                                                       Spray rate = 19 gpm

                            14


                            12
    Cooling Effect, deg F




                            10


                             8


                             6


                             4


                             2


                             0
                             13.5   14          14.5              15         15.5   16   16.5
                                                   Wet Bulb Depression, deg F
             Data Correlation
                               T De c k DB -T Fa n DB v s (T De c k DB -T De c k W B ) x S p ra y R a te
                                                  S in g le -C e ll T e s t in g , C ro c k e t t
                      14

                      12

                      10
TDeckDB -TFanDB , F




                       8

                       6

                       4

                       2

                       0
                           0       50     100       150       200         250        300        350    400   450   500
                                             (T D e c k D B -T D e c k W B )x S p ra y R a te , F x g p m
                          Correlation vs.
                          Spray Rate
                                                     (T De c k DB -T Fa n DB) /(T De c k DB -T De c k W B ) v s S p ra y R a te
                                                                       S in g le -C e ll T e s t in g , C ro c k e t t
                                         0.8
(TDeckDB -TFanDB )/(TDeckDB -TDeckWB )




                                         0.6



                                         0.4



                                         0.2



                                         0.0
                                               0.0               5.0               10.0                  15.0            20.0     25.0
                                                                                   S p ra y R a te , g p m
El Dorado Energy
Center
El Dorado ACC
Effect on
Backpressure
                                 Turbine Back Pressure vs Spray Rate - July
                                                           ElDorado LLC

                                              Amb DB = 115 F
                         7
                                         110 F                       Steam Flow = 1,067,000 #/hr

                         6
    Back Pressure, "Hg




                                    105 F

                                   100 F
                         5
                                   95 F

                                  90 F
                         4

                         3

                         2
                             0           20           40        60          80       100           120
                                                       Spray Rate, gpm/cell
Power Recovery

                                             Recovered Power vs Start Temp vs Spray Period

                        4,000
                                     Water Budget = 35,210,000 gallons

                        3,800
                                                                                               Spray Period - 10am-8:59pm

                        3,600
    Recov Power, MWHr




                        3,400

                                     Water Budget = 26,410,000 gallons
                        3,200

                                                                                                                10am-8:59pm
                        3,000
                                                                                     10am to 7:59pm


                        2,800
                                                                             10am-6:59pm

                        2,600
                                                                                                      11am-6:59pm

                        2,400
                                85                     90                   95                        100                     105
                                                             Start Temperature for Spraying, F
Now What?

   Showstoppers
    - Surface wetting
    - Rainback
     - Cost (Approx $0.5 M for 40 cell, plus $0.7 M
  to 2.0M for water treatment and storage)
   Approaches
    - Nozzle choice/location
    - Flow modeling
    - Demisters

								
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