cogeneration in india.ppt

Simultaneous production of two forms of energy – Thermal Energy – Electricity / Mechanical Energy

Loses up to 70%

Fuel(100%)

Conventional Plant

Efficiency is 30-40%

Loses up to 10%

Fuel(100%)

Cogeneration Plant

Efficiency up to 70-90%

Source: IEA, CHP: Evaluating the Benefits of Greater Global Investment (2008).

Sector

Potential, MW

Realizable Potential, MW

Distilleries

3500

2500

Cement

600

400

Chemicals

900

600

Fertilizers

1200

750

Metal Industry

1060

700

Sugar

5000

3000

Refineries

800

600

Paper & Pulp

1000

750

Textile

1200

800

BCHP

650

400

Other Sector

750

500

Total

16000

11500

Natural gas Coal Biomass Bagasse (waste product from sugar cane processing)

Waste gas Sludge gas from sewage treatment plant Methane from landfills and coal bed methane

Liquid fuels (oil) Renewable gases

Steam turbine Gas turbine

Reciprocating engine Other classifications: Topping cycle Bottoming cycle

Widely used in CHP applications

Oldest prime mover technology Capacities: 50 kW to hundreds of MWs Thermodynamic cycle is the “Rankine cycle” that uses a boiler Most common types Back pressure steam turbine Extraction condensing steam turbine

Steam exits the turbine at a higher pressure that the atmospheric

HP Steam

Fuel

Boiler

Turbine

Condensate Process

LP Steam

Figure: Back pressure steam turbine

HP Steam

Steam obtained by extraction from an intermediate stage Remaining steam is exhausted Relatively high capital cost, lower total efficiency Control of electrical power independent of thermal load

Boiler

Turbine

Fuel LP Steam Condensate

Process

Condenser

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

Open Brayton cycle: atmospheric air at increased pressure to combustor Old/small units: 15:1 New/large units: 30:1

Exhaust Gases Condensate from Process HRSG Steam to Process Combustor Fuel

Exhaust gas at 450600 oC G

High pressure steam produced: can drive steam turbine

Generator Compressor

Turbine

Air

Figure: Open cycle gas turbine cogeneration

Heat Source

Working fluid circulates in a closed circuit and does not cause corrosion or erosion Any fuel, nuclear or solar energy can be used

Heat Exchanger

G Generator Compressor

Turbine

Condensate from Process

Steam to Process

Figure: Closed Cycle Gas Turbine Cogeneration System

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

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 Reducing environmental impact

Conserving limited resources of fossil fuels Saving money On-site production of electricity generation

Promoting liberalization in energy markets

Industrial CHP Sugar industry – bagasse CHP Others District system CHP IT industry Industrial parks Mixed residential/commercial districts Small Scale Systems

Depends very much on tariff system Heat Avoid cost of separate heat production Electricity 1) Less purchase (kWh) 2) Sale of surplus electricity 3) Peak shaving (kW) Carbon credits (future)

Lack of a clear definition of cogeneration or CHP There has not been an economy-wide study of CHP potential (and associated benefits) Lack of an approved methodology for calculating CO2 emission reductions from CHP Limited availability of competitively priced turbines and engines for CHP Lack of pipeline networks for district cooling

Grid Ancillary Services Bulk Power Power Quality and CHP Remote Power and CHP

Energy Management, future CHP and Sell to Grid

Base-load, and Industrial Cooling, Heat and Power

Cogeneration improves energy efficiency…..…….if heat is used in a proper way

www.cogeneration.org www.uschpa.org www.iea.org www.cogenindia.org www.ieachp.org