A PRESENTATION ONCOGENERATION

presented BY :-Pratik gupta (eee 6TH SEM )

DR. C.V. RAMAN INSTITUTE OF SCIENCE & TECHNOLOGY

CONTENTS:-

Introduction

Types of cogeneration systems

Benefit of cogeneration

Energy efficiency

Introduction:-

Cogeneration is also called CHP system.Generation of multiple forms of energy in

one system: heat and powerDefined by its “prime movers”

• Reciprocating engines• Combustion or gas turbines, • Steam turbines• Microturbines• Fuel cells

Type of Cogeneration Systems:-

• Steam turbine

• Gas turbine

• Reciprocating engine

• Other classifications: - Topping cycle

- Bottoming cycle

Steam Turbine Cogeneration System:-

• Widely used in CHP applications

• Oldest prime mover technology

• Capacities: 50 kW to hundreds of MWs

• Thermodynamic cycle is the “Rankin cycle” that uses a boiler

• Most common types• Back pressure steam turbine• Extraction condensing steam turbine

• Steam exits the turbine at a higher pressure than the atmospheric

Back Pressure Steam Turbine

Fuel

Figure: Back pressure steam turbine

Advantages:-Simple configuration-Low capital cost-Low need of cooling water -High total efficiency

Disadvantages:-Larger steam turbine

Boiler Turbine

Process

HP Steam

Condensate LP Steam

• Steam obtained by extraction from an intermediate stage

• Remaining steam is exhausted

• Relatively high capital cost, lower total efficiency

Extraction Condensing Steam Turbine

Boiler Turbine

Process

HP Steam

LP SteamCondensate

Condenser

Fuel

Figure: Extraction condensing steam turbine

• Operate on thermodynamic “Brayton cycle”• atmospheric air compressed, heated, expanded• excess power used to produce power

• Natural gas is most common fuel

• 1MW to 100 MW range

• Rapid developments in recent years

• Two types: open and closed cycle

Gas Turbine Cogeneration System

• Open Brayton cycle: atmospheric air at increased pressure to combustor

Open Cycle Gas Turbine

Air

G

Compressor Turbine

HRSG

CombustorFuel

Generator

Exhaust Gases

Condensate from Process

Steam to Process

• Old/small units: 15:1 New/large units: 30:1

• Exhaust gas at 450-600 oC

• High pressure steam produced: can drive steam turbine

Figure: Open cycle gas turbine cogeneration

• Working fluid circulates in a closed circuit and does not cause corrosion or erosion

• Any fuel, nuclear or solar energy can be used

Closed Cycle Gas Turbine

Heat Source

G

Compressor Turbine

Generator

Condensate from Process

Steam to Process

Heat Exchanger

Figure: Closed Cycle Gas Turbine Cogeneration System

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• Used as direct mechanical drives

Reciprocating Engine Cogeneration Systems

Figure: Reciprocating engine cogeneration system

• Many advantages: operation, efficiency, fuel costs

• Used as direct mechanical drives

• Four sources of usable waste heat

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© UNEP 2006

• Supplied fuel first produces power followed by thermal energy

• Thermal energy is a by product used for process heat or other

• Most popular method of cogeneration

Topping Cycle

Bottoming Cycle

• Primary fuel produces high temperature thermal energy

• Rejected heat is used to generate power

• Suitable for manufacturing processes

• Increased efficiency of energy conversion and use

• Lower emissions, especially CO2• Ability to use waste materials• Large cost savings• Opportunity to decentralize the electricity

generation• Promoting liberalization in energy markets

Benefits of Cogeneration (CHP)

Energy Efficiency Opportunities

Steam turbine:• Keep condenser vacuum at optimum value

• Keep steam temperature and pressure at optimum value

• Avoid part load operation and starting & stopping

Steam Turbine Cogeneration System

Energy Efficiency Opportunities

Gas Turbine Cogeneration SystemGas turbine – manage the following parameters:

• Gas temperature and pressure• Part load operation and starting & stopping• Temperature of hot gas and exhaust gas• Mass flow through gas turbine• Air pressure

THANK YOU

Any query???