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Russia Power - March 2013Unrestricted © Siemens AG 2013 All rights reserved.

Flexible steam turbine solutions for combined heat and power in combined cycle power plants

Christian Helesch, Product Line Management Steam Turbine

Unrestricted © Siemens AG 2013 All rights reserved.

Table of content

Russia Power - March 2013 Christian Helesch / Product Line Management Steam Turbine

Siemens solutions for combinedheat and power in CCPPs

Requirements of district heating

Combined heat and power in different power plants

Development of power plant types

Unrestricted © Siemens AG 2013 All rights reserved.Russia Power - March 2013 Christian Helesch / Product Line Management Steam Turbine

Fossil market view and forecast for whole installed capacity within expectations of analysts

International Energy Agency2030 - IEA

5.000

CoalOilGasNuclear

External Study

EIA: Energy Information Administration, July 2011(most recent available data)CERA: Cambridge Energy Research Associates (Vortex Scenario (=mid Scenario)), Oct. 2012 WEO: World Energy Outlook 2012 (New Policies Scenario), Oct. 2012Figures rounded

World Nuclear & Fossil Power Capacity (Large and Small) per fuel type [GW]

Combined cycle power plant market is rising in the next yearAlso a increase in combined heat and power in CCPPs is forecasted

2011

4.000

34%1459

42%2234


Combined heat and power in different power plants -Design

Low pressure turbine inner casing for CCPP without extraction

Low pressure turbine inner casing for SPP with extraction for feed water preheating

Turbines for CCPP generally are not prepared for steam extraction


Combined heat and power in different power plants -Thermodynamics

Steam Power Plant• Complete power output from steam

turbine• Steam flow reduced by feed water

preheating

Combined Cycle Power Plant• 2/3 power output from gas turbine• 1/3 power output from steam turbine• Steam low increased by inductions

Steam mass flow of SPP is twice as much as the steam mass flow of CCPP(for CHP for the same power plant output)


Requirements for district heatingDifference between district heating and process steam

District heating steam• Small range of extraction pressure level• Floating requirements for amount of steam

(Summer/Winter)• High deviation in plant load vs.

requirement of constant pressure level

Process steam• Wide range of extraction pressure level• Mainly constant over the year

(desalination, distillation columns etc.)• Deviation in plant load vs. requirement of

constant pressure level

Max. pressure level defines feed water temperature• 150°C 6bar*• 70°C 0.4bar*

*with 10% piping loss and 5K terminal temperature difference


Requirements for district heatingDriver for performance

The main drive for performance with regard to heat extraction is the number of extractions stages in the steam turbine

Example for a CCPP with about 600MW electrical output


Combined heat and power in different power plantsChallenges for CCPP

• Generally no extraction in CCPPdesign changes for extraction flangesrising performance with rising number of extraction stages

• High and floating steam extraction, even in part loadbig extraction flanges in relation to turbine sizeadditional measure for low load: erosion and cooling

• Constant pressure level for every load neededaggregate to throttle steam required


Siemens solutions for combined heat and power in CCPPs – 1 stage extraction

Combined HP/IP turbine LP turbine

IP inlet

HP inlet

HP exhaust(cold reheat)

Butterfly valves in cross over pipe to realize const extraction pressure

Extraction form outer casing of combined HP/IP turbine

or

or Extraction from cross over pipe

LP exhaust(to condenser)


Siemens solutions for combined heat and power in CCPPs – Throttle aggregate

Cross over pipe of steam turbine in a 450MW CCPP and butterfly valve (diameter 1500mm)

Butterfly valve with actuator



Pros• Low and high level arrangement possible• Applicable for Singleshaft and Multishaft• Low complexity for upgrade

Cons• Performance during heat extraction• Complexity of piping for low level

arrangement

IP extraction line for max extraction of 260MWth in a 450MW CCPP Non return valve IP extraction line




IP inlet

HP inlet



Second extraction in LP casing

Butterfly valve

Extraction from cross over pipeor Extraction form outer casing of combined HP/IP turbine

or



Pros• Performance during heat extraction• Low and high level arrangement possible• Applicable for Singleshaft and Multishaft

Cons• High complexity of piping for low level

arrangement• Complexity for an upgrade

LP extraction line from LP casing in a 450MW CCPP




IP inlet

HP inlet



Third extraction in LP casing

Butterfly valve

Extraction from cross over pipeor Extraction form outer casing of combined HP/IP turbine

or

Second extraction in L casing

LP extractions



Pros• High performance during heat extraction• Low and high level arrangement possible• Applicable for Singleshaft and Multishaft

Cons• Highest complexity of piping for low level

arrangement• High complexity for an upgrade

Piping for a 2 stage extraction in a 450MW CCPP


Some references

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