Technical and economical experiences with large

ORC systems using industrial waste heat streams

of cement plants
2. ORC-Symposium - 6. November 2015- HSLU
Hochschule Luzern - Technik & Architektur Horw

Urs Herzog - Holcim Technology Ltd

Agenda

• Waste Heat Streams and Potential for Waste Heat Recovery

in Energy Intensive Industries (EI-Industry)

• Waste Heat to Power (WHP) Option in Cement Industry

• Holcim ORC - WHP Projects - Key Data

• ORC-WHP Experiences made / Learning’s

• Economics

• Findings & Conclusion

Technical and economical experience with large ORC systems, 2015-11-06 © 2015 Company 2
There exist a significant potential in industry sectors worldwide
to improve energy efficiencies and valorize waste heat streams

• Studies1) estimate that 20-50% of all energy inputs into industrial

process leaves in the form of waste heat.
• The global total final energy consumption of the industry
was 107 EJ in 20112)
• Overall efficiency is estimated to be ~ 50%
• The total saving by applying Best Available Technology (BAT)
is estimated to be 25 EJ (= 24%)
• The rest is considered to be
wasted as heat streams in
solid, liquid and gaseous forms
at different temperatures
levels (25 – 800 °C)
Industrial
Waste Heat Streams
1) Energetics and US DOE, 2004
© 2015 Company 3
2) M. Bendig 2015, (IEA 2004e)
Petroleum & coal, chemical, iron & steel and non-metallic
mineral product gave highest waste heat usage potential

Fig: US industries; manufacturing sector waste heat Inventory (list not exhaustive)
(source: ICF International study 2015 4))

• Largest potential is within Petroleum & coal products; Majority of waste heat
stream is on temperatures above 230°C
• The 4 top potential industries have a significant waste heat streams with
temperatures above 230°C
• Waste heat valorization potential in Cement as part of “Non-Metallic Mineral
Products” will be presented in more details
Technical and economical experience with large ORC systems, 2015-11-06 © 2015 Company 4
Energy Flow Diagram of a cement plant clinker burning kiln
Thermal Energy Input & Waste Heat Streams
210 kWh/tcl Thermal Energy Input: 780 kWh / tcem
Kiln Exit Gas @ 290- 400 °C Electrical Energy Input: 110 kWh / tcem
23%

Radiation & Convection

Losses 100 kWh/tcl
Cooler Exit Gas @ 250 -350 °C
9%
11%

55% 2%
Clinker Formation
Clinker Sensible Heat

Technical and economical experience with large ORC systems, 2015-11-06 © 2015 Company
5
Cement kiln Waste Heat to Power (WHP) Systems mostly use
Water-Steam-Rankine Cycle (WSRC). -- For temperatures < 300°C
Organic-Rankine Cycle (ORC) is the better option.
• Momentary ~ 900 WHP system are running worldwide (highest number in China)
• Majority of systems using steam turbines (WSRC) at temperatures > 350°C
• Average yield of WHRP in cement is ~ 30-40 kWhel/tcl
• Less than 10 WHP system using ORC concept with the objective to use low
temperature waste heat streams
• Two heat-exchangers
designed for high dust
load (cleaning system)
• Two intermediate heat
transfer loops
(either thermal oil or
pressured water)
• ORC cycle with
recuperator
(hydrocarbon, silicone
or refrigerator fluid)
• Air or water (evaporation)
cooled condenser
© 2015 Company 6
In the field of Waste Heat to Power, Holcim gained experiences from
numerous commercial operating and research projects
(since 2008 Holcim build more than 35 WHP plants)

Höver (Germany) Rohoznik (Slovakia) Alesd (Romania)

extra-low-temp: 90 -110°C low-mid-temp: 230 - 390°C low-mid-temp: 230 - 390°C
100 KWe, ORC; 2013 ~ 5 MWe; ORC, 2014 3.7 MWe; ORC, 2012

Huaxin Cement (China)

mid-temp: ~ 380°C
26 WSRC systems in 23 plants
Untervaz (Switzerland) ~ 235 MWel; 2007-2013
low-mid-temp: 250 - 360°C
2.0 MWe; ORC; 2013 / 2015 Hon Chong (Vietnam)
mid-temp: ~ 380°C
6 .2 MWe; WSRC; 2012

Chekka (Lebanon)
Mid- and low-temp
(from Diesel Generator 16 MWel) Gagal / Rabryiawas (India)
2.1 WSRC + 0.9 ORC MWel, 2013 mid-temp: ~ 380°C
4.3 MWe, WSRC, 2013
6.0 MWel WRSC, 2015
WHR systems running (3 + 30)
Research
Commercial Operation ORC
Commercial Operation WSRC (steam) © 2015 Company
7
 In 2012 Holcim Romania commissioned the world first
ORC-WHP power plant using kiln and cooler gas streams

Cement kiln system

with two exhaust gas
heat-exchangers

Kiln exhaust Kiln exhaust

Heat-exchanger 2 Heat-exchanger 1

© 2015 Company 8
ORC-WHR power plant with 4 MWel (gross) power output

ORC power plant building ORC power plant with evaporator,

recuperator and condenser

ORC Flow Sheet

three heat sources:
• kiln exhaust exit 1 (left)
• kiln exhaust exit 2 (right)
• cooler air exit

© 2015 Company
 Holcim Switzerland commissioned 2013 / 2015 a “roof-top”
ORC-WHP power plant using kiln and cooler gas streams
Cement kiln WHP Preheater gas
system with two gas tie-in
heat sources: Cooler gas
• kiln exhaust gas tie-in
• cooler air
Cooler gas
ORC Flow Sheet heat-exchanger
with two gas heat-exchangers (left)
Preheater gas
ORC fluid pre-heater and evaporator (middle)
heat-exchanger
ORC turbine & generator (right bottom)
and Air cooled condenser (right top) Preheater gas
booster-fan

Air cooled
condenser

ORC fluid
Heat-exchangers
Turbine-
generator

ORC fluid
tanks
© 2015 Company 10
 Untervaz WHP ORC-WHR power plant
with 2.3 MWel (gross) 1.9 MWel (net) power output
Horizontal gas-flow pre-heater Air Cooled Condenser (four modules)
HEX bare tubes with dust rapper • no water consumption; no plume
• noise issue; higher aux. consumption (4x48kW)

Technical and economical experience with large ORC systems, 2015-11-06 © 2015 Company 11
Höver cement plant extra-low heat WHP research pilot (2013)
EU FP7 program: “LOVE” project
“Low-temperature heat valorization towards electricity production”
(waste stream gas temperature < 120°C)

Cooling Control System and

tower data acquisition

Heat extraction Water heat- Turbine-Container Water-Container

Hybrid transfer-circuit Generator & VFC Neutralization
Heat-Exchanger Condenser ORC evaporator
© 2015 Company 12
 Hybrid heat-exchanger (patented) to extract latent heat
at extra-low temperatures from wet exhaust gas

Fin-and-tube
heat-exchanger
(HEX1)

Condensing Unit
Packed-Column
(PCU)

Technical and economical experience with large ORC systems, 2015-11-06 © 2015 Company 13
 Heat Recovery and ORC System Parameter of WHP installed
by Holcim (2008 to 2015)
Plant Type / Size Heat- Heat- ORC turbine ORC fluid Cooling
Inlet Temp Exchanger Transfer Make / Type / Evaporation-
Make / Type Coupling Stages/ Gear / temp /
Cleaning / Axe-sealing Gross Eff
Spare Cap.
Alsed; Commercial JFE Thermo-Oil Turboden Silicone-oil Wet
Romania H-cross-flow Press-Water Axial, Multi-Stg (MM) Water-
4 MWel Gearless
Hammering Serial ~ 240°C evaporation
230 / 390°C >100% reserve Oil sealing 19.3%
Untervaz; Commercial HTA Press-Water Atlas-Copco Isobutane Dry
Switzerland H-cross-flow Parallel Radial, Single-Stg = 140-160°C Air cooled
2.3 MWel Gear
Hammering ~ 16-17%
250 / 360°C 60% reserve N2 sealing
Rohhoznik; Commercial Transparent Thermo-Oil Turboden Cyclo- Wet
Slovakia V-parallel-flow Parallel Ax-Rad, Multi-Stg pentane Water-
~ 5 MWel Gearless
Hammering ~ 210°C evaporation
310 / 360°C >100% reserve Oil sealing ~ 21%
Höver; Research Armines Water Cryostar R 245fa Wet
Germany Direct- Radial, Single-Stg (R1234yf) Water-
100 kWel Gearless
condensing = 64°C !! evaporation
< 120°C self-cleaning Variable-speed 5.9-6.2 %
hermetic housing
Technical and economical experience with large ORC systems, 2015-11-06 © 2015 Company 14
Experiences made with ORC type WHP systems

• Performance of ORC Systems

• Exhaust gas input temperatures: 360 – 390°C
• Efficiency (gross) 16 - 21%; depending on HEX, ORC system and fluid
• Internal (captive) consumption ~15% - 20% (water-steam system ~ 7%)
• Extra-low temperature system with 105°C gas temp.  Eff = 6%
• Reliability / Availability
• All WHP plant have a high availability: 96-98%
• Heat exchanger design is crucial (heat transfer area and dust removal system)
• Operation:
• Operation & Maintenance Cost = 2.4 €/MWh;
• Fully automatic operation (no additional shift personnel)
• Water cooling systems need chemical additives and regular water analysis

• System Cost / Cost of power produced

• Investment cost: 3’300 – 4’500 k€/MW (extreme = 5500 €/MW)
• Power cost (LCOE): 81 – 109 €/MWh

Technical and economical experience with large ORC systems, 2015-11-06 © 2015 Company 15
Issues / Learnings (1)
Overall Efficiency / Complexity / Cost Driver
• Gas Heat-Exchanger (HEX) & Heat Transfer
• Proper design (cross-flow) and sufficient exchanger surface (+ 100% reserve)
• Adequate dust removal (hammering) and transportation system
• Heat Transfer Loop: Non-pressured system preferred (Thermal-oil)
• Best Option: Avoid Heat Transfer Loop (Direct heat concept)

• Turbine type
• Multi-Stage expander (to fully use available pressure level)
• Good part-load performance (WHP source vary widely – in contrast to geo-thermal plants)
• Low rotation / gearless
• Oil / liquid turbine-axe sealing (avoid addition N2 system)

• ORC fluid
• Select fluid to match temperature level (supplier-design)
• Flammable fluid (hydrocarbons) require EX-Design

• Cooling
• Water-evaporation Systems (Wet) are more effective, need less energy and are lower in cost
compared to Air Cooled Condenser - but they need water chemicals and regular care
Technical and economical experience with large ORC systems, 2015-11-06 © 2015 Company 16
Issues / Learnings (2)
Exhaust Gas Heat-Exchanger (HEX) Size & Design

• “Japanese” Design:
Thermal capacity: 9.7 MW
Exchanger Area: 4950 m2
Specific Area: 0.5 m2 / kW

• “German” Design:
Thermal capacity: 10.4 MW
Exchanger Area: 3110 m2
Area reserve: 60 %
Specific Area: 0.3 m2 / kW

Technical and economical experience with large ORC systems, 2015-11-06 © 2015 Company 17
 Issues / Learnings (3)
Maximal use of available Energy
• Loss of Exergy
• Some system design results in high Exergy Loss (do not use available temperature level)

• Gas Inlet temperature is quit high but HEX heat transfer • Gas Inlet temperature is extra-low; HEX heat transfer
coefficient is low and Isobutane fluid properties do not coefficients are OK – but fluid with gliding evaporation
match very well temperature (azeotrope mixture) would be more adequate

Technical and economical experience with large ORC systems, 2015-11-06 © 2015 Company 18
Economics

• I’m an engineer:
• I want to develop solutions –
but it must be economical

Prof. Dr. Lino Guzzella; President ETH Zürich

“Quote: Zürich 21.08.2015; Swiss-US Energy Innovation Days”

Technical and economical experience with large ORC systems, 2015-11-06 © 2015 Company 19
WHP generated power has slightly lower cost compared to
“standard” Renewable Energy production cost –
– but WHP is not eligible for “RE Incentives”
Industry Investment Conditions
• WACC = 8%
• Pay-back = 10 years
Wind • Inflation = 0.5%
Wind *)
off-shore • No incentives considered
Swiss Alps

Wind WHR high

on-shore *) WHR low

European
Solar PV EI-Industry
Germany *) power cost
WHR target

*) Sources: Fraunhofer ISE, Stromgestehungskosten Erneuerbare Energien, Studie November 2013,

Technical and economical experience with large ORC systems, 2015-11-06 © 2015 Company 20
WHP System Investment Cost contributes for
96% of the resulting electricity price
• O&M cost are marginal (3 - 4%)
• Cost reduction measures must focus in lowering investment costs

ORC power plant

cost are significant
(some saving potential) Biggest saving potential are in civil, ducts, heat-exchanger and heat
transfer loop (~ 50% of system investment cost)
Technical and economical experience with large ORC systems, 2015-11-06 © 2015 Company 21
Findings and Conclusion
• ORC based mid-temperature WHP in cement plants proved to work well
and are economic viable for power prices > 90 €/MWh
• Innovations are required to further reduce investment cost
• Apply simple design (location, duct work, cooling, auxiliaries, etc.)
• Use modular, standard and mass-produced components

• Design, installation and operation are crucial for

high performing applications
• Use experiences made (Industry has learned from good and bad practices)
• Comprehensive modeling and simulation tools are required to:
• determine best systems design
• define optimal system parameters for all possible operation points
(part-load performance is crucial for WHP applications)

• In the near future, WHP in EI-Industry will compete with Renewable Energy
Systems, mainly Solar PV (Fraunhofer ISE)

Technical and economical experience with large ORC systems, 2015-11-06 © 2015 Company 22