Qualifizierung von Flüssigsalz-Komponenten in der · PDF fileQualifizierung von Flüssigsalz-Komponenten in der DLR-Anlage TESIS ... Federsel, K., Wortmann, J., Ladenberger, M. (2015)

Qualifizierung von Flüssigsalz-Komponenten

in der DLR-Anlage TESIS

Dr. Thomas Bauer, Dr. Christian Odenthal, Dr. Alexander Bonk,

Dr. Antje Seitz

Deutsches Zentrum für Luft- und Raumfahrt (DLR)

Institut für Technische Thermodynamik, Stuttgart/Köln

Köln, 6.7.2016

DLR

www.DLR.de/TT • Slide 2 > Thermal Energy Storage > Thomas Bauer

Contents

- Overview of high-temperature TES technology

- Molten salt TES technology

- Material qualification aspects

- Qualification in the molten salt plant TESIS

- Summary


Institute of Engineering Thermodynamics Prof. André Thess, Director

Jörg Piskurek, Vice Director

Thermal Process

Technology

Dr. A. Seitz

Electrochemical

Energy

Technology

Prof. A. Friedrich

Systems Analysis

and Technology

Assessment Dr. Ch. Schillings /

C. Hoyer-Klick

~ 190 staff in Stuttgart, Köln, Hamburg, and Ulm

~ 20 Mio. EUR annual budget with 50% third party funding

„We are the scientific pathfinder for the energy storage industry“

Energy System

Integration

Prof. A. Thess

Prof. J. Kallo

Computational

Electrochemistry

Prof. A. Latz


Locations and employees

DLR:

Approx. 8000 employees across

33 institutes and facilities at

16 sites.

Offices in Brussels, Paris,

Tokyo and Washington.

Thermal energy storage group:

- Stuttgart

- Cologne

Cologne

Oberpfaffenhofen

Braunschweig

Goettingen

Berlin

Bonn

Neustrelitz

Weilheim

Bremen Trauen

Lampoldshausen

Stuttgart

Stade

Augsburg

Hamburg

Juelich


Department Thermal Process Technology

Dr. Antje Seitz

Thermal Power Plant Components

Dr. Stefan Zunft

Regenerator and solid media

storage

High temperature

heat exchangers

Thermal Systems

for Fluids

Dr. Thomas Bauer

Molten salt storage

Thermal Systems with Phase Change

Dr. Dan Bauer

Latent heat storage

Thermo-chemical Systems

Dr. Marc Linder

Thermochemical Storage

Thermal Upgrade

H2-Storage

Alternative Fuels

Dr. Uwe Dietrich

Regenerative power in liquid hydrocarbons

Technoeconomic

evaluation


Overview of high-temperature TES technology

Commercial technologies

- Sensible heat storage in solids

- Regenerator (1 bar, 1200 °C)

- Sensible heat storage in liquids

- Steam Accumulator (40 bar, 250°C)

- Thermal oil (1 bar, 300 °C)

- Molten salt (1 bar, 550 °C)

Molten Salt, Source: Andasol 1 Steam accumulator/Ruth's, Source: PS10 Regenerator/Cowper


Sensible heat storage in MOLTEN SALTS

Installed global capacity for grid-connected storage

Source: https://www.iea.org/newsroomandevents/graphics/2015-06-30-installed-global-capacity-for-grid-connected-storage.html

- CSP grid-connected molten salt storage power > 1500 MWel in 2015

- CSP grid-connected molten salt storage capacity > 30 GWhth in 2015

https://www.iea.org/newsroomandevents/graphics/2015-06-30-installed-global-capacity-for-grid-connected-storage.html






















Focus of the DLR group

System aspects

Components

Process technology

Material (Upscaling)

aspects



Characteristics of molten salt

- Liquid state over large temperature range (e.g., Solar Salt 260 - 560 °C)

- Ability to dissolve a relatively large amount of compounds (corrosion may occur)

- Low vapor pressure and high stability

- Low viscosity

- High heat capacity per unit volume

- Several salts are inexpensive/available

- Often nontoxic, nonflammable and no explosive phases

Nitrate salt in a

glass beaker

Salt crystals at room

temperature

Model of molten Sodium

Chloride (Source: Baudis 2001)



Classification of alkali nitrate/nitrite salt examples

Ion

No.

System Classification Example System with Tm

2 Single salt NaNO3 306 °C; KNO3 334 °C

3 Binary system, common anion K,Na//NO3 222 °C (“Solar Salt” system)

3 Binary system, common cation Na//NO2,NO3 230 °C

4 Ternary additive, common anion Ca,K,Na//NO3 ~130 °C (HitecXL)

4 Ternary additive, common anion K,Li,Na//NO3 ~120 °C (LiNaK)

4 Ternary reciprocal K,Na//NO2,NO3 142 °C (Hitec)

5 Quaternary additive, com. anion Ca,K,Li,Na//NO3 90-110 °C

5 Quaternary reciprocal Li,Na,K//NO2,NO3 80 °C

6 Quinary reciprocal Ca,Li,Na,K//NO2,NO3 ~70 °C (DLR)

(examined systems at DLR)



Ideal chemistry of molten nitrate salts

S

teel

N2 O2

NO3-

Cation Anion

K+ Na+


S

teel


Chemistry of molten nitrate salts with side reactions

N2 O2

CO32-

NO2-

CO2

O2-

NO2

NO3-

Cation Anion

OH-

H2O

CrO42- K+

Na+

NO

Sources:

Federsel, K., Wortmann, J., Ladenberger, M. (2015) Energy Procedia, 69, pp. 618-625.

Nissen, D.A., Meeker, D.E. (1983), Inorganic Chemistry, 22, pp. 716-721

Bradshaw, R.W., Dawson, D.B., De La Rosa, W., et al. (2002) Report SAND2002-0120.

Bauer, T., Pfleger, N., Laing, D., et al. (2013) Chapter 20 in "Molten Salt Chemistry: from Lab to Applications"



DLR Material research #1

- Development of alternative salt mixtures with

- reduced melting temperature < 140 ºC

- thermal stability up to 700 ºC

- Investigation of the decomposition mechanisms

of nitrates with parameters such as...

- Temperature

- Salt mixture type

- Atmospheric conditions

Chloride salt

test rig

Nitrate salt

test rig

Halogen salt with (left) and without (right)

decomposition during dehydration

Phase diagram including

HITEC salt mixture

Thermogravimetry evolved gas

analysis for stability tests


- Interactions of molten salts with

- metals / corrosion

- natural stone / filler materials

- Thermal properties determination

- Post-analysis of salt composition


DLR Material research #2

Quartzite with and

without molten salt Metallic corrosion

in molten salt flow

Rheometer for

viscosity values

DSC for heat

capacity values

Ion chromatography

for salt composition

UV-VIS Spectrometer for

salt composition


Commercial two-tank technology

Direct storage system Indirect storage system

for solar tower systems for parabolic trough systems

(Storage medium = HTF) (Storage medium ≠ receiver HTF)



TESIS:store - storage test section

Aim:

- Demonstration of single-tank thermocline concept with filler

Operating Parameters:

- Operation temperature 150 - 560 °C

with NaNO2, NaNO3, Ca(NO3)2, KNO3, LiNO3 salt mixtures

- Storage capacity (ΔT=250K):

200 kWh/m³ with 20 m³ and 4 kg/s

Research topics:

- Heat / mass transfer, thermomechanics

- Material compatibility

- Operational aspects, scaling issues

- System integration

Potential

- Previous examination at Sandia

estimate 20 -37 % cost reduction



TESIS:store - storage test section



TESIS:com - component test-bench

Aim:

• Test and qualification of molten salt

components for research and industry

(e.g. valves, receiver tubes,

measurement & control)

• Examine operational molten salt aspects

(e.g. freezing events)

Operating Parameters:

• Temperature of 150 - 560 °C with

NaNO2,NaNO3,Ca(NO3)2,KNO3,LiNO3

• max. thermal gradient 50 K/s

• max. mass flow of 8 kg/s

• max. heating power 420 kW

• max. cooling power 420 kW



TESIS:com - component test-bench



Test facility for thermal energy storage in molten salt (TESIS)



Qualification aspects

- Material

- Molten salt quality

- Metallic corrosion

- Accuracy of thermal properties

- Instrumentation

- Reliability (e.g., thermal shock, leakage/seals, corrosion,

freezing issues)

- Accuracy (e.g. volume flow, temperature, level, pressure)

- Storage systems

- Boundary condition (with/without salt melting, auxiliary systems, heat

exchanger, steam generator)

- Thermal and hydraulic performance (losses, gradients)

Thank you for your attention !

Institute of Engineering Thermodynamics (ITT), Köln

Email: [email protected]

mailto:[email protected]

Documents

Qualifizierung von Flüssigsalz-Komponenten in der · PDF fileQualifizierung von Flüssigsalz-Komponenten in der DLR-Anlage TESIS ... Federsel, K., Wortmann, J., Ladenberger, M. (2015)