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Schneider Process Automation Power Industry Solutions`Power plant basics – An overviewBy Rodney Berg

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Power Plant Basics

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Components of a Power Plant

> Key1. Cooling tower 10. Steam governor valve 19. Superheater 2. Cooling water pump 11. High pressure turbine 20. Forced draught fan 3. Transmission line (3-phase) 12. Deaerator 21. Reheater 4. Unit transformer (3-phase) 13. Feed heater 22. Air intake5. Electric generator (3-phase) 14. Coal conveyor 23. Economizer 6. Low pressure turbine 15. Coal hopper 24. Air preheater 7. Condensate pump 16. Pulverized fuel mill 25. Precipitator 8. Condenser 17. Boiler drum 26. Induced draught fan 9. Intermediate pressure turbine 18. Ash hopper 27. Chimney Stack

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Boiler types

RBE RBC Benson UP

Power output60 to 800MW 50 to 1000MW 75MW and over 350MW and over

Main steam press.

Main steam Temp.

Boiler type

Natural circulation Once-through

Subcritical Subcritical / supercritical

up to 566ºC up to 630ºC

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How a coal-fired plant works

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Process description ….1. Coal Supply – Coal fed and then crushed and fed through the conveyor belt to the plant

2. Coal Mill – The coal is fine crushed and fed to the boiler along with air for combustion

3. Boiler – The de-mineralized water fed through the boiler tubes is converted into steam from the heat from the combustion process.

4. Precipitator & Stack – The exhaust from the boiler is released into the atmosphere after it passes through the precipitator which removes the fly ash before the flue gases are dispatched to the atmosphere

5. Turbine, Generator - The hot steam from the Boiler is passed through the turbine HP section and it hits the blades at 540 0C and 130 Kg Bar Pressure causing the turbine to rotate rapidly. This causes the generator which is coupled to the turbine to rotate its shaft producing electric current.

6. Cooling Water System – The steam discharged from the turbine is cooled with cooling water in the condensers. The cold water is heated by the steam and again fed to the boiler to to start the generation process again.

7. Water Treatment Plant – This is for purification of the water being fed to the boiler to reduce sludge etc.

8. Precipitators , Ash System – The fly ash and bottom ash are removed from plants and hauled to disposal site or ash lagoons.

9. Substation, Transformer, Transformer lines – Once the electricity is generated transformers increase the voltage so that it can be carried across the transmission lines.

10. The electricity voltage is again reduced to be fed to the cities and towns at substations.

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BottomAshSystem

EconomizerHoppers

F DFan

BOTTOMASH

HOPPER

CoalBunker

Conveyors

Pulverizers

Load

Gen.HP IP L P

Turbine

Econ-omizer

Re-Heat

SuperHeater

DRUM

Condenser

P AFan

IDFan

HPFW

Htr

LPFW

Htr

AshTransfer

PrecipitatorsStackGas Scrubber

EmissionsMonitor

Flyash

Cond.Pump

BFPDeaerator

CoolingWater

Feeder

Downcomers

Risers

Air Heater

Power Plant Detailed Process Map Water Vapor &

Scrubbed Gases

General

Water

Sump

WATERTREATMENT

SettlingPond

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Power Plants - Basic Control LoopsCombustion Control

> Fuel Control

- Coal or Gas or Oil or Combinations

> Air Flow Control

- Forced Draft Fan Control

Furnace Draft Control

> Induced Draft Fan Controls

Feed-water Control

> BFP (Boiler Feed-water Pump) Control

> Feed-water Valve Control

Steam Temperature Control

> Spray (attemperator) Valve Controls

> Damper Controls

> Gas Recirculation Fan Controls

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Boiler Schematic

Fuel

Sec air

Reheat steam

SH steam

ConcentrationCOO2

NOx

Furnace temp.

Exhaust temperature

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ADSInterface

UnitMaster

BoilerMaster

FuelMaster Air

SteamTemp Feedwater

Boiler Turbine

TurbineMaster

Mill 1 Mill n IDFans

FDFans

Furnace Draft

S-heatSpray

R-heatSpray

BF-Pump

TurbineValves

Load Demand

Boiler Control System – Modulating Control

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BottomAshSystem

EconomizerHoppers

F DFan

BOTTOMASH

HOPPER

CoalBunker

Conveyors

Pulverizers

Load

Gen.HP IP L P

Turbine

Econ-omizer

Re-Heat

SuperHeater

DRUM

Condenser

P AFan

IDFan

HPFW

Htr

LPFW

Htr

AshTransfer

PrecipitatorsStackGas Scrubber

EmissionsMonitor

Flyash

Cond.Pump

BFPDeaerator

CoolingWater

Feeder

Downcomers

Risers

Air Heater

Power Plant Detailed Process Map Water Vapor &

Scrubbed Gases

General

Water

Sump

WATERTREATMENT

SettlingPond

Boiler Control

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Boiler ControlsFollowing are the major control areas in a Boiler

> Supply of water to the boiler,> Combustion of fuel in the furnace,> Steam pressure> Steam temperature, and > Furnace pressure, are all a part

Now as a Instrumentation and controls supplier we should be able to do the above with our DCS system

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Power Plant Operation ModesNormal Mode • This is also known as the turbine-leading-boiler mode or (Boiler-lagging). As its name implies, it is

normally the preferred mode of operation, as it is designed to serve the needs of the power grid. • If this mode is selected, the unit’s operator specifies generator electrical output as the set-point:

the operator sets the target electric power output [say, in MW, or in % of Full Power (FP)], and the target rate of change of power [e.g., in % FP/s].

• The control program (running in the station computer) is called the Unit Power Regulator (UPR). • The UPR continuously compares the actual generator power to the setpoint.Alternate Mode• This is also known as the boiler-leading-turbine mode (or turbine-lagging). This is not normally

the preferred mode of operation, but is used under certain circumstances, especially if the reactor power has to be strictly controlled.

• If this mode is selected, the unit’s operator specifies reactor power as the setpoint: the operator sets the target reactor power output [say, in % of reactor Full Power (FP)], and the target rate of change of reactor power [e.g., in % FP/s].

• The RRS continuously compares the actual reactor power to the setpoint. • If there is a difference, there is a “reactor-power error”.

Invensys proprietary

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Power Plants – Advanced Control LoopsAdvanced Control

> Like Boiler Optimization> Soot Blower Optimization> NOx Reduction> Data Acquisition SystemsPlant Performance Calculations> Boiler and Turbine Efficiency Calculations> Energy Management (Load Dispatch) Systems> Load Shedding schemes> Energy control and Management Systems

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Power Plants - Additional Control LoopsBalance of Plant Controls (Miscellaneous Controls)

> Water Inventory Controls- Deareator Level Control- Hot Well Level Controls- Condensate Flow Controls

> Turbine Cooling Oil Temperature Controls> Generator Cooling Oil Temperature Controls> Air Pre-Heater Temperature (Cold End Temperature) Controls

Water Treatment Plant ControlsCooling Tower ControlsFuel Handling

> Coal Handling> Fuel Oil, pressure, flow, & temperature control> Gas pressure control

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BottomAshSystem

EconomizerHoppers

F DFan

BOTTOMASH

HOPPER

CoalBunker

Conveyors

Pulverizers

Load

Gen.HP IP L P

Turbine

Econ-omizer

Re-Heat

SuperHeater

DRUM

Condenser

P AFan

IDFan

HPFW

Htr

LPFW

Htr

AshTransfer

PrecipitatorsStackGas Scrubber

EmissionsMonitor

Flyash

Cond.Pump

BFPDeaerator

CoolingWater

Feeder

Downcomers

Risers

Air Heater

Power Plant Detailed Process Map Water Vapor &

Scrubbed Gases

General

Water

Sump

WATERTREATMENT

SettlingPond

Emissions Monitoring

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Power Plants - Emission Control SystemsPower Plant Emissions

> Particulate Matter- Fly-ash

> Sulfur Oxides- SO2 - Sulfur Dioxide

> Nitrogen Oxides- NOx - Nitrogen oxides

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Power Plant EmissionsControl of Power Plant Emissions

> ESP’s - Electrostatic Precipitators> FF’s - Fabric Filters (Bag Houses)> FGD’s - Flue Gas Desulfurization Systems (Scrubbers)> SCR’s - Selective Catalytic Reduction

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FGD’s – Flue Gas Desulphurization

• Flue gas desulphurization, or “scrubbing,” is a complex process that uses lime or limestone to absorb sulfur dioxide emissions before they can be released into the air, making the power plant a cleaner energy producer.

• With environmental regulations getting continuously stricter, effective FGD systems are crucial for SO2 compliance.

• A number of variables can affect the performance and cost efficiency of a flue gas scrubber, including lime slurry flow, pH levels, oxidation levels, and even stack temperature.

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Combined Cycle Power Plant

A combined cycle is a combination of two or more thermal cycles within a single power plant, where the intention is to increase the efficiency

over that of the single cycles

That is, 2 stand alone inefficient (~30%) energy cycles put together in the right way yields

1 reasonably efficient (~60%) energy cycle.

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Two Cycles Put Together -Thermodynamics

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Why Combined Cycle Power Plants?

• Highest efficiency of any power plant (approaching 60%)• Lowest emissions of any current fossil fuel power plant• Lowest installed and operational costs for power generation• High levels of operational flexibility• Shorter lead times than conventional fossil-fuel-fired steam plant• Suitability for highly efficient co-production schemes • Option of using coal and other fuels via gasification

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3Identifying, Types and Offering

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Power Industry Technology Coal-fired power plant

Coal

Boiler

Steam turbineand generator

Dust collector

Combustionsystem

Desulphurisationsystem

Denitrificationsystem

HRSGGas Turbine

Control Systems

Generator

Steam Turbine

Combined cycle power plant

Hydro power plant

Nuclear power plant Geothermal power plant

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Drum/Once-Through/Fluidized Bed Coordinated control Combustion Drum level Furnace pressure Steam temperature Load runback Load block

Enterprise Operations Management Real-time Operations Management Operational Dashboards Maintenance & inventory management Fleet Generation Management Asset Management

Environmental control Electrostatic / Mechanical Precipitator Wet / Dry Flue Gas Desulfurization Baghouse Selective Catalytic Reduction Selective Non Catalytic Reduction

Burner Management Auto-purge & pre-light Emergency shutdown protection Burner-pulverizer automation Boiler control integration Burner-front equipment

Balance of plant control BFP Turbine Control Condensate control Condenser hotwell Feedwater heaters Make-up water Turbine lube oil temperature Generator H2 temperature Automatic Sootblowing Motor logic Steam coil air heater Switchyard

Boiler control

Turbine controls Speed governor Frequency governor Overspeed protection On-line valve test Auto-synchronization Automatic startup Vibration Monitoring Hydraulics

Fuel control Gas Oil Coal Unloader Crushing Drying Stacker Reclaimer

Simulators High fidelity Operator training Control Checkout Loop tieback

Data acquisition Generation optimization AGC Network security Distribution management Switchyard/Substation SCADA

Optimization Heat Rate Emissions Smart Sootblowing Steam Temperature

Generation, Distribution & Substation Automation

Aim*Historian Periodic Logs Sequence of Event Post Event Review Equipment Run Time Tag Out Group Measurement Display Performance Calculations Controllable Losses Loop / Alarm Management

Power Industry Applications overview

AssetManagementRisk & SafetyManagement

OperationalPerformance

Real TimeOperations Management

Real TimeBusiness Performance

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The Power Industry Solutions Set Generation T&D, Metering Corporate

AGC Network security Distribution management Switchyard/Substation SCADA

Distribution & Substation Automation Enterprise Operations

Management Real-time Operations Management Operational Dashboards Maintenance & inventory management Fleet Generation Management Asset Management Corporate Energy ManagementEnvironmental

Electrostatic / Mechanical Precipitator Wet / Dry Flue Gas Desulfurization Baghouse Selective Catalytic Reduction Selective Non Catalytic Reduction

Burner Management

Balance of plant control

Boiler control

Turbine controls

Fuel control

Simulation andTraining

Optimization

Emissions Control

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Schneider Electric PA Power Solutions Footprint

Generating Units

EnergyPortfolio

OTS

APC

Risk & Safety Management

Foxboro/Triconex Controls

Generation TransmissionDistribution

Foxboro SCADAEAM/Smart Signal/SwanTech

Real-time Operations ManagementLoop/Alarm Management

Real-time Business Performance

Generating Fleet Trading

SE PA offers solutions that span the full value chain of the Power Industry

AssetManagement

Risk & SafetyManagement

OperationalPerformance

Real TimeOperations Management

Real TimeBusiness Performance

Other Offerings fromControls & Safety

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SE PA Solutions for Power1. I/A Series Distributed Control System

2. Safety Solutions-Triconex In Power Plant

3. Fleet Generation Management System

4. PADO – Performance Monitoring and Diagnostic Optimization and PRISM Offerings

5. Advanced Process Controls – Connoisseur for the Power Industry

6. Operator Training Simulator

7. Invensys Life Cycle Management Program