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International Workshop on:
DESIGN OF SUBSYSTEMS FOR CONCENTRATED SOLAR POWER TECHNOLOGIES19-22 December 2013. Jodhpur (India)
Direct Steam Generation
CIEMAT-Plataforma Solar de Almería
E-mail: eduardo.zarza@psa.es
Eduardo Zarza MoyaLoreto Valenzuela Gutiérrez
International Workshop: “Design of Subsystems for CSTP Technologies”19-22 December 2013, Jodhpur (India)
Contents
Advantages and disadvantages of the DSG process
Current status of the DSG technology
Direct Steam Generation
Introduction
International Workshop: “Design of Subsystems for CSTP Technologies”19-22 December 2013, Jodhpur (India)
Contents
Advantages and disadvantages of the DSG process
Current status of the DSG technology
Direct Steam Generation
Introduction
International Workshop: “Design of Subsystems for CSTP Technologies”19-22 December 2013, Jodhpur (India)
Steam Production with Linear Solar Concentrators
a) using a Heat Transfer Fluid
So
lar
Fie
ld
Steam
Generator
Feed pump
Oil expansion
tank
T1 T2
T1 T2 + 10 K
Process
T1 T2
T1 T2 + 10 K
Steam
Liquid water
b) with Flashing
Flash tank
Water
recirculation
Expansion
valve
P1P2P1>>P2
Feed water
pump
P1P2>>P2
Saturated steam
Liquid water
So
lar
Fie
ld
Process
International Workshop: “Design of Subsystems for CSTP Technologies”19-22 December 2013, Jodhpur (India)
Steam Production with Linear Solar Concentrators
c) with Direct SteamGeneration (DSG)
Feed water
pump
Steam
Liquid waterS
ola
r F
ield
Process
International Workshop: “Design of Subsystems for CSTP Technologies”19-22 December 2013, Jodhpur (India)
Different sections in the rows of a DSG solar field
Solar Radiation
2L 3L1L
To
Po
Direct Steam Generation
m
Preheating SperheatingEvaporation
International Workshop: “Design of Subsystems for CSTP Technologies”19-22 December 2013, Jodhpur (India)
vl = m · (1-x) / (Atubo · l)
vg = (m · x) / (Atubo · g)
Two-phase Flow Pattern Map
for an horizontal pipe
0,01
1
1
0,1
0,1
0,001
0,01
10
10
100Sp
erf
icia
lli
qu
id v
elo
cit
y /
(m
/s)
Superficial steam velocity / (m/s)
Annular
Intermittent
Estratified
Bubbly
Steam Production with Linear Solar Concentrators
c) with Direct SteamGeneration (DSG)
Feed water
pump
Steam
Liquid water
So
lar
Fie
ld
Process
International Workshop: “Design of Subsystems for CSTP Technologies”19-22 December 2013, Jodhpur (India)
Two different “Bubbly” configurations
Disperse-Bubbly Flow
Direct Steam Generation
A
A’
A
A’
A
A’
A
A’
A
A’ Sección A-A’
A
A’ Sección A-A’
Foggy-Bubbly FlowSection A-A’
Section A-A’
International Workshop: “Design of Subsystems for CSTP Technologies”19-22 December 2013, Jodhpur (India)
Slow-Intermittent Flow
Plug-Intermittent Flow
Section A-A’
Section A-A’
A
A’
A
A’
A
A’
A
A’
A
A’
A
A’
A
A’
Two different “Bubbly” configurations
Direct Steam Generation
International Workshop: “Design of Subsystems for CSTP Technologies”19-22 December 2013, Jodhpur (India)
vl = m · (1-x) / (Atubo · l)
vg = (m · x) / (Atubo · g)
Two-phase Flow Pattern Map
for an horizontal pipe
0,01
1
1
0,1
0,1
0,001
0,01
10
10
100Sp
erf
icia
lli
qu
id v
elo
cit
y /
(m
/s)
Superficial steam velocity / (m/s)
Annular
Intermittent
Estratified
Bubbly
Steam Production with Linear Solar Concentrators
c) with Direct SteamGeneration (DSG)
Feed water
pump
Steam
Liquid water
So
lar
Fie
ld
Process
International Workshop: “Design of Subsystems for CSTP Technologies”19-22 December 2013, Jodhpur (India)
The Three Basic DSG Processes
Once-Through Boiler
Lowest Costs
Least complexity
Best Performance
Controllability ?
Flow Stability ?
T
u
r
b
i
n
e
Feed pump
Solar Collectors
Injection Process
Better Controllability
Flow stability equally good
More complex
Higher investment costs
T
u
r
b
i
n
e
Injectors
Feed pump Solar Collectors
Recirculation Process
Better Flow Stability
Better Controllability
More complex
Higher investment costs
Higher parasitics
Feed pump
Separator
T
u
r
b
i
n
e
Recirculation pump
Solar Collectors
International Workshop: “Design of Subsystems for CSTP Technologies”19-22 December 2013, Jodhpur (India)
Contents
Advantages and disadvantages of the DSG process
Current status of the DSG technology
Direct Steam Generation
Introduction
International Workshop: “Design of Subsystems for CSTP Technologies”19-22 December 2013, Jodhpur (India)
Comparison between the DSG and the HTF (oil) technologies
Smaller environmental risks because oil is replaced by water
Higher steam temperature (maximum steam temperature with oil = 385ºC)
Advantages of the DSG technology:
The Direct Steam Generation Process
International Workshop: “Design of Subsystems for CSTP Technologies”19-22 December 2013, Jodhpur (India)
Scheme of a typical HTF plant with parabolic trough collectors
Thermal oils currently available have a thermal limits of 398ºC. There is a significant
degradation above 400ºC
Typical HTF Solar Thermal Power Plant
295 ºC Oil
395 ºC Oil
Steamgenerator
Deaerator
Reheater
Oil expansion vessel
Steam turbine
CondenserG
So
lar
Fie
ld
Preheater
Superheated Steam (104bar/380ºC)
Reheated steam 17bar/371ºC
G
International Workshop: “Design of Subsystems for CSTP Technologies”19-22 December 2013, Jodhpur (India)
Comparison between the DSG and the HTF (oil) technologies
Smaller environmental risks because oil is replaced by water
Higher steam temperature (maximum steam temperature with oil = 385ºC)
Advantages of the DSG technology:
The Direct Steam Generation Process
The overall plant configuration is more simple
International Workshop: “Design of Subsystems for CSTP Technologies”19-22 December 2013, Jodhpur (India)
Simplified Scheme of typical HFT and DSG solar thermal power plants
Direct Steam Generation versus HTF Technology
Auxiliary boiler
Degasifier
Condenser
Steam turbine
GDV Plant
Steam at 104 bar/400 ºC
Liquid water at 114 bar / 120 ºC
Superheater
Steam Generator
Degasifier
Reheater
Oil expansion tank
Auxiliary heater
Solar Field
Steam turbine
Condenser
Oil at 295 ºC
Oil at 390 ºC
Steam at104 bar/371 ºC
Oil
Cir
cu
it
HTF Plant
International Workshop: “Design of Subsystems for CSTP Technologies”19-22 December 2013, Jodhpur (India)
Comparison between the DSG and the HTF (oil) technologies
Smaller environmental risks because oil is replaced by water
Higher steam temperature (maximum steam temperature with oil = 385ºC)
Advantages of the DSG technology:
The Direct Steam Generation Process
The overall plant configuration is more simple
Lower investment and O&M costs and higher plant efficiency
International Workshop: “Design of Subsystems for CSTP Technologies”19-22 December 2013, Jodhpur (India)
Lower LCOE of DSG versus HTF Plants
LEC changes by different DSG options
compared to oil reference
(TES = storage, OT = once-through,
PCM = PCM storage).
A comparative study of HTF and DSG performed by DLR for a 100 MWe plant
with a 9-hour TES has shown that:
• Scaling-up beyond a certain limit is not recommended for DSG plants (two 50 MWe plants together have a lower LEC than a single 100 MWe plant)
• The size and type of TES has a great impact on the LEC
International Workshop: “Design of Subsystems for CSTP Technologies”19-22 December 2013, Jodhpur (India)
Comparison between the DSG and the HTF (oil) technologies
Smaller environmental risks because oil is replaced by water
Higher steam temperature (maximum steam temperature with oil = 385ºC)
Solar field control under solar radiation transients
Disadvantages of the DSG technology:
Advantages of the DSG technology:
The Direct Steam Generation Process
The overall plant configuration is more simple
Lower investment and O&M costs and higher plant efficiency
International Workshop: “Design of Subsystems for CSTP Technologies”19-22 December 2013, Jodhpur (India)
Influence of solar radiation transients on feed-water flow distribution
The Direct Steam Generation Process
'1L
Radiación solar
2L 3L1L
To >Ti
Po <Pi
'3L'2L
m
Pi, Ti
T’ < To
P’ > Po
Radiación solar
m
Pi, Ti
Radiación solar
"1L "2L "3L
T > To
P” < Po
m
Pi, Ti
International Workshop: “Design of Subsystems for CSTP Technologies”19-22 December 2013, Jodhpur (India)
Comparison between the DSG and the HTF (oil) technologies
Smaller environmental risks because oil is replaced by water
Higher steam temperature (maximum steam temperature with oil = 385ºC)
Solar field control under solar radiation transients
Instability of the two-phase flow inside the receiver tubes
Disadvantages of the DSG technology:
Advantages of the DSG technology:
The Direct Steam Generation Process
The overall plant configuration is more simple
Lower investment and O&M costs and higher plant efficiency
International Workshop: “Design of Subsystems for CSTP Technologies”19-22 December 2013, Jodhpur (India)
Comparison between the DSG and the HTF (oil) technologies
The Direct Steam Generation Process
The Ledinegg instability
Mass flow, m
Pre
ssu
re d
rop
,
P
Pressure drop versus mass flow in a row of PTC wit DSG at
Constant intel temperature, outlet pressure and heat
Only Steam
Only liquid
Typical performance curve
of a centrifugal pump
P
P’
•P”
•
•
0)
cteEdm
P
International Workshop: “Design of Subsystems for CSTP Technologies”19-22 December 2013, Jodhpur (India)
Comparison between the DSG and the HTF (oil) technologies
Smaller environmental risks because oil is replaced by water
Higher steam temperature (maximum steam temperature with oil = 385ºC)
Solar field control under solar radiation transients
Instability of the two-phase flow inside the receiver tubes
Temperature gradients at the receiver pipes
Disadvantages of the DSG technology:
Advantages of the DSG technology:
The Direct Steam Generation Process
The overall plant configuration is more simple
Lower investment and O&M costs and higher plant efficiency
International Workshop: “Design of Subsystems for CSTP Technologies”19-22 December 2013, Jodhpur (India)
Uneven heat transfer at the steel absorber pipe
Receiver pipe
Parabolic trough
concentrator
hliquid
hliquid
Direct Steam Generation
International Workshop: “Design of Subsystems for CSTP Technologies”19-22 December 2013, Jodhpur (India)
Temperature gradients in the steel absorber pipes
Uneven heat transfer at the steel absorber pipe
Direct Steam Generation
International Workshop: “Design of Subsystems for CSTP Technologies”19-22 December 2013, Jodhpur (India)
DSG-related projects and studies since 1980
Theoretical studies by SERI (1982)
The ATS (Advance Trough System) project by LUZ,(1987-1991)
DSG with Linear Solar Concentrators
Experiments by ZSW at the HIPRESS test facility (1992-1994)
The project PRODISS
The GUDE project experiments at Erlangen (1992-1995)
The project ARDISS (1994-1997)
R+D activities at UNAM (Mexico, 1976- up to date)
The DISS project (1996-2001)
The RealDISS project (2009-2011)
The INDITEP project (2002-2005)
The DUkE project (2012-2014)
International Workshop: “Design of Subsystems for CSTP Technologies”19-22 December 2013, Jodhpur (India)
Contents
Advantages and disadvantages of the DSG process
Current status of the DSG technology
Direct Steam Generation
Introduction
International Workshop: “Design of Subsystems for CSTP Technologies”19-22 December 2013, Jodhpur (India)
Curent Status
DSG with Linear Solar Concentrators
Technical feasibility of the DSG process in linear solar concentrators has
been proven. There are several DSG solar thermal power plants in operation
International Workshop: “Design of Subsystems for CSTP Technologies”19-22 December 2013, Jodhpur (India)
DSG with Linear Solar Concentrators
Plant TSE-1, Thailand
5 MWe
34 bar, 340 °C
Technology by Solarlite
International Workshop: “Design of Subsystems for CSTP Technologies”19-22 December 2013, Jodhpur (India)
DSG with Linear Solar Concentrators
Plant Puerto Errado-2, Spain
30 MWe
55 bar, 270 °C
Technology by Novatec&ABB
International Workshop: “Design of Subsystems for CSTP Technologies”19-22 December 2013, Jodhpur (India)
Accurate simulation&design tools for DSG solar fields have been developed
Ball-joints for water/steam at 100bar/500ºC have been successfully tested.
The best configuration for commercial DSG solar fields is a mixture of injection
and recirculation. This configuration has been experimentally evaluated at PSA
DSG with Linear Solar Concentrators
Technical feasibility of the DSG process in linear solar concentrators has
been proven. There are several DSG solar thermal power plants in operation
Curent Status
International Workshop: “Design of Subsystems for CSTP Technologies”19-22 December 2013, Jodhpur (India)
DSG with Linear Solar Concentrators
Scheme of a DSG row of collectors with Recirculation
( 20%)
( 7%)
Feed water
Water recirculation
Preheating + Evaporation
Water
inyection
Steam superheating
Water/steam
separator
International Workshop: “Design of Subsystems for CSTP Technologies”19-22 December 2013, Jodhpur (India)
Compact and cost-effective water/steam separators have been developed
DSG with Linear Solar Concentrators
Accurate simulation&design tools for DSG solar fields have been developed
Ball-joints for water/steam at 100bar/500ºC have been successfully tested.
The best configuration for commercial DSG solar fields is a mixture of injection
and recirculation. This configuration has been experimentally evaluated at PSA
Technical feasibility of the DSG process in linear solar concentrators has
been proven. There are several DSG solar thermal power plants in operation
Curent Status
International Workshop: “Design of Subsystems for CSTP Technologies”19-22 December 2013, Jodhpur (India)
Direct Steam Generation
Water/steam separators for DSG
Classic water/steam separator Compact water/steam separator
International Workshop: “Design of Subsystems for CSTP Technologies”19-22 December 2013, Jodhpur (India)
A cost-effective thermal energy storage technology for DSG still to be
developed
DSG with Linear Solar Concentrators
Accurate simulation&design tools for DSG solar fields have been developed
Ball-joints for water/steam at 100bar/500ºC have been successfully tested.
The best configuration for commercial DSG solar fields is a mixture of injection
and recirculation. This configuration has been experimentally evaluated at PSA
Technical feasibility of the DSG process in linear solar concentrators has
been proven. There are several DSG solar thermal power plants in operation
Compact and cost-effective water/steam separators have been developed
Technical feasibility of the Once-Through option must be fully investigated
Curent Status
International Workshop: “Design of Subsystems for CSTP Technologies”19-22 December 2013, Jodhpur (India)
DSG with Linear Solar Concentrators
Upgraded PSA DISS Facility for Once-Through mode
View of the new DISS solar field for Once-Through at 500ºC /112bar
International Workshop on:
DESIGN OF SUBSYSTEMS FOR CONCENTRATED SOLAR POWER TECHNOLOGIES19-22 December 2013. Jodhpur (India)
Eduardo Zarza MoyaLoreto Valenzuela Gutiérrez
CIEMAT-Plataforma Solar de Almería
E-mail: eduardo.zarza@psa.es
End of the Presentation
Thank you very much for your attention !!
Direct Steam Generation
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