DESIGN OF

VAPOR (STEAM &

AMMONIA) TURBINE

FOR KALINA CYCLE FOR KALINA CYCLE

WORKSHOP ON ADVANCED ENERGY EFFICIENT TECHNOLOGIES

JUNE 2012, NEW DELHI & CHENNAI

ContentContent

Intent For Design of the Kalina Cycle Turbine Intent For Design of the Kalina Cycle Turbine

IntroductionIntroduction

Rankine Cycle Steam TurbineRankine Cycle Steam Turbine

Kalina Cycle Vapor TurbineKalina Cycle Vapor Turbine

Design of Ammonia Mixture TurbineDesign of Ammonia Mixture TurbineDesign of Ammonia Mixture TurbineDesign of Ammonia Mixture Turbine

Design Process involved in TurbineDesign Process involved in Turbine

Challenges in Turbine Design for Kalina CycleChallenges in Turbine Design for Kalina Cycle

Product Development CycleProduct Development Cycle

Properties of the Water & Ammonia MixtureProperties of the Water & Ammonia Mixture

ContentContent

1.1. Intent For Design of the Kalina Cycle TurbineIntent For Design of the Kalina Cycle Turbine

2.2. IntroductionIntroduction

3.3. Rankine Cycle Steam Turbine Rankine Cycle Steam Turbine

4.4. Kalina Cycle Vapor TurbineKalina Cycle Vapor Turbine

5.5. Design of Ammonia Mixture TurbineDesign of Ammonia Mixture Turbine

6.6. Design Process involved in TurbineDesign Process involved in Turbine

7.7. Challenges in Turbine Design for Kalina CycleChallenges in Turbine Design for Kalina Cycle

8.8. Product Development CycleProduct Development Cycle

9.9. Properties of the Water & Ammonia Mixture Properties of the Water & Ammonia Mixture

Intent For Design of the Kalina Cycle TurbineIntent For Design of the Kalina Cycle Turbine

�Arani power system achieved an historic milestone in the Indian turbine manufacturing

industry by bagging a 5.27MW Kalina cycle vapor turbine order from FLSmidth, Chennai.

� It is a waste heat recovery from Cement plant. This type of turbine is the first of this

kind being designed and manufactured in India.

� This turbine is ranked third in the world in power generation capacity.

�With 3 decades expertise in design, development, manufacturing and commissioning of

steam turbines by the Arani power system technical team, it could able to over come the

challenges in the design of turbine sealing, control systems and selection of the special

materials.

INTRODUCTIONINTRODUCTION

�Compared to the conventional century-old Rankine cycle, a Kalina cycle power plant

may offer efficiency gains of up to 50percent for low heat energy sources such as

geothermal brine at 150°C to 210°C

�. Gains of up to 20 percent may be realized for higher temperature heat sources such as

direct fired boilers and exhaust gases from a gas turbine. i.e. bottoming cycle of a

combined cycle plant.

�It is likely that Kalina cycle plants will even cost less to build than Rankine cycle plants

of equal output.

� Up to 30 percent savings for low heat applications and up to 10 percent savings for

direct fired or bottoming cycle plants have been approximated.

�The Kalina cycle is principally a “modified” Rankine cycle. The transformation starts

with an important process change to the Rankine cycle - changing the working fluid in the

cycle from a “pure” component (typically water) to a “mixture” of ammonia and water.

INTRODUCTION Cont…INTRODUCTION Cont…

Rankine Cycle Steam TurbineRankine Cycle Steam Turbine

Kalina Cycle Vapor TurbineKalina Cycle Vapor Turbine

Kalina Cycle Vapor TurbineKalina Cycle Vapor Turbine

Comparison of Rankine & Kalina Cycle Vapor TurbineComparison of Rankine & Kalina Cycle Vapor Turbine

In Scope

Basic Diagram of Thermodynamic Advantages

Design of Ammonia Mixture TurbineDesign of Ammonia Mixture Turbine

�Conventional axial flow steam turbines can be used in Kalina cycle plants.

This is possible because the molecular weight of ammonia and water are

similar - 17 for ammonia and 18 for water.

�Turbines for Kalina cycle plants will also be smaller and therefore less

expense than turbines in Rankine cycle plants.

�This is because Kalina cycle plants can utilize back pressure turbines as

condensing turbines. Turbines in Rankine cycle plants exhaust to a condenser

under vacuum, whereas Kalina cycle plants exhaust to a condenser under

pressure. This creates a big difference in specific volumes and therefore a big

difference in the size of the flow area in the exhausting turbine.

Design Process involved in Turbine Design Process involved in Turbine

� Vapor Flow Path Design

� Material Selection

� Journal and Thrust Bearing Selection

� Mechanical Seal Design

� Control systems for seal and Turbine� Control systems for seal and Turbine

� Rotor dynamics

� 3D Modeling

� Manufacturing drawings

Challenges in Turbine Design for Kalina CycleChallenges in Turbine Design for Kalina Cycle

� The Materials used in Kalina cycle should be free from Copper. If copper

is present in the Material the ammonia will react with Copper and leads

to corrosion.

� The Ammonia and Steam are not allowed to leak to the atmosphere. So,

complete leak proof sealing system is required for the Turbine. Special

seals to be used in addition to the labyrinth seal and Special seals to be used in addition to the labyrinth seal and Special

constructional features are to be provided in Throttle Valve, ESV etc.

Seal DesignSeal Design

HP leak to exhaust pipe

N2 Injection

Mixture (Steam+NH3) +N2

Leakage to blow down tank (1bar (A))

Inlet

Turbine

N2 Injection

Mixture (Steam+NH3)+N2

Leakage to blow down tank (1bar (A))

Exit

Atmosphere

Turbine

(NH3+Steam)

Atmosphere

Leak Off steam

Circumferential Seal Design

Product Development CycleProduct Development Cycle

DESIGN CODES & STANDARDSDESIGN CODES & STANDARDS

ARANI Steam Turbines are designed as per following

Turbine Design IEC 45, API 612, NEMA

SP23

Balancing API 612, ISO 1940

Rotor Dynamics API 612

Vibration Monitoring System API 670

Performance Test IEC 953

Technology & ToolsTechnology & Tools

THERMAL DESIGN

Meanline code(2D) for Preliminary design

SLEQ (Quasi 3D) for Optimum Design

In-house code for preparation for HMBD

MODELLING & DESIGN

Pro/E for 3D Modeling & Manufacturing Drawings

AutoCAD for Conceptual Design

SECTIONAL VIEW SECTIONAL VIEW -- TURBINE ASSEMBLY TURBINE ASSEMBLY

3D Models3D Models

HP CASINGStraight Blade

Technology & ToolsTechnology & Tools

CFD ANALYSIS

Bladegen for Modelling of Blades

Turbogrid for Flow domain & Meshing

CFX for Analysis and Simulation

STRUCTURAL ANALYSIS

ANSYS for Analysis

ROTORDYNAMIC ANALYSISROTORDYNAMIC ANALYSIS

In-House code based on Transfer Matrix Method

XL ROTOR based on FEM method

TORSIONAL & SHORT CIRCUIT ANALYSIS

TORVIB based on Transfer Matrix Method

HP Blade Flow SimulationHP Blade Flow Simulation

HP Casing Structural AnalysisHP Casing Structural Analysis

Rotor dynamic Lateral AnalysisRotor dynamic Lateral Analysis

Torsional & Short Circuit AnalysisTorsional & Short Circuit Analysis

• Evaluate dynamic behavior of TG train

• Determine Torsional natural frequencies

• Evaluate resonance occurrence with Campbell diagram & select couplings

Generator Gear BoxTurbine

Couplings

Properties of the Water & Ammonia MixtureProperties of the Water & Ammonia Mixture

Ammonia-water mixtures have many basic features unlike that of either pure water

or pure ammonia. A mixture of the two fluids behaves like a totally new fluid

altogether.

There are four primary differences.

1. An ammonia-water mixture has a varying boiling and condensing temperature.

Conversely, both pure water and pure ammonia have constant boiling and

condensing temperatures.

2. The thermo-physical properties of an ammonia-water mixture can be altered by 2. The thermo-physical properties of an ammonia-water mixture can be altered by

changing the ammonia concentration. The thermo-physical properties of water

and ammonia are fixed.

3. Ammonia-water has thermo-physical properties that causes mixed fluid

temperatures to increase or decrease without a change in the heat content. The

temperature of water or ammonia do not change without a change in energy.

4. The final difference is not really a change in a basic feature, but rather an

important change in a fluid property. This is the freeze temperature. Water

freezes at a relatively high temperature of 0°C, while pure ammonia freezes at

-78°C.Solutions of ammonia-water have very low freezing temperatures.

Phase DiagramPhase Diagram

The essence of the Kalina cycle takes advantage of the first feature change - the ability of an ammonia-water mixture, at any given pressure. to boil or condense at a “variable”temperature.

Ammonia-Water Phase Diagram

Varying Boiling TemperatureVarying Boiling Temperature

The temperature of the heat source drops as it gives up its energy to the working fluid. Because of the variable boiling temperature, the temperature rise of an ammonia-water mixture, in a counter-flow heat exchanger, more closely follows the straight line temperature drop of a sensible heat source

Heat Exchange Process - Heat Source to 3450 kPa

Ammonia-Water Solution

Heat Exchange Process - Heat Source to 3450 kPa Water

Comparison at different PressuresComparison at different Pressures

Heat Exchange Process - Heat Source to 690 kPa Water

Heat Source Process - Heat Source to 55 kPa Water

Varying Condensing TemperatureVarying Condensing Temperature

�Both “steam” in a Rankine cycle and ammonia-water vapor in a Kalina cycle will

exhaust from a condensing turbine at or near their respective vapor saturation

points. However, given equal condenser cooling water temperatures, the

ammonia water will have a significantly higher pressure and temperature

than the steam.

The higher pressure is a result of ammonia being more volatile than water. The �The higher pressure is a result of ammonia being more volatile than water. The

higher temperature is a result of the variable condensing temperature feature of

an ammonia-water mixture.

RecuperationRecuperation--CondensationCondensation

Heat Exchange Process – Recuperation-Condensation

There is also a secondary benefit of this Kalina cycle design. Since the temperature

rise of the cooling water for the ammonia- water can be higher than that for

condensing steam, the cooling water flow rate for the ammonia-water can be less

than that required for the steam. This means smaller cooling towers, pumps and

piping, along with lower auxiliary power requirement for pumping and cooling

Lower fans. This can result in significant capital cost savings for the cooling

system and further increases in the “net” power plant output for the Kalina cycle.

Specific Composition ChangeSpecific Composition Change

The Kalina cycle has a design option that can effectively reduce the pressure and

temperature of the vapor at the turbine exhaust. Taking a page out of an

ammonia absorption refrigeration design book, the Kalina cycle has the ability to

readily change the thermo-physical properties of the working fluid in different

parts of the cycle by changing the ratio of the ammonia-water mixture.

Phase Diagram – Absorption-Condensation

Another feature of the Kalina cycle is that the composition of the ammonia-water

mixture, and therefore the thermo-physical properties of the working fluid can be

readjusted throughout the entire system if operating parameters change.

Operation Below Freezing TemperaturesOperation Below Freezing Temperatures

Kalina cycle plants, however, can take advantage of this opportunity. Ammonia

has a very low freezing temperature. Just a small amount of ammonia in water

greatly reduces the freezing temperature. For example, even a lean 25/75

ammonia-water solution has a very low freezing temperature of -51°C. As a result,

condensation temperatures of ammonia-water fluids can go down to arctic

temperatures.

�Arani Power Systems is a STEAM TURBINE manufacturer and supplier of

Turbo-Generator (TG) packages based in Hyderabad, India. Arani power

Operations cover from CONCEPT to COMMISSIONING of TG Packages of

capacities 4 to 48MW and other services up to 150MW. Arani Power designs and

manufactures high quality, customized and most efficient steam turbines to meet

unique needs of different industries like Independent, captive and cogeneration

About ARANI POWER SYSTEMS LIMITEDAbout ARANI POWER SYSTEMS LIMITED

unique needs of different industries like Independent, captive and cogeneration

power plants.

�Eminent experts in specialized disciplines form the bedrock on which ARANI

is founded. The in-depth experience of our team members that spans over more

than three decades with well known Steam turbine manufacturing companies

across the country and overseas, is to fulfill the needs of the Power industry

across the globe.

�Evolving to meet ever increasing demand, ARANI uses the latest and superior

technology in developing steam turbines according to the global standards.

ARANI designs and delivers cost effective customized products to international

standards.

About ARANI POWER SYSTEMS LIMITED Cont..About ARANI POWER SYSTEMS LIMITED Cont..

�Arani Power Systems has an excellent infrastructure of operates of well

established R&D, and Engineering departments, state of the art manufacturing

facility inclusive of mechanical run test facility, good supply chain management

systems in place, sound Trouble shooting capability. Further it has a good Erection

& commissioning, after sales and Renovation & Modernization departments to

meet and exceed customer’s requirements.