Double Reheat TechnologyThe next step to optimized efficiency

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Answers for energy.

Modern Steam Power Plants: On the Path to Increased Efficiency

Technologies on test

One possible route to greater efficiency in modern steam power plants is the so-called 700°C technology. And effi-ciency can indeed be increased through this innovative solution. However, increased efficiency normally means higher steam parameters. And as the required pressures and temperatures increase, so does the stress on materi-als, inducing additional risks and maintenance costs.

A cost-intensive solution

To increase efficiency with steam temperatures beyond 700°C more resistant turbines are required. Materials with higher resistances could therefore be the solution. However this technology is still in its infancy and there-fore expensive.

*Net efficiency achievable with this technology – project-specific efficiency may vary.

SPP Bergkamen 747 MW

SPP Boxberg 906 MW

Wai Gao Qiao III 2x1000 MW

700°C technology

The requirements of power suppliers for their modern steam power plants have changed considerably in the past few years. The increasing demand for reliable base load supply, combined with resource scarcity and environmental regulations, drives the need for greater efficiency.

39%* SPP efficiency

43%* SPP efficiency

47%* SPP efficiency

> 50%* SPP efficiency

1981 1996 2009 > 2020

190 bar / 530 / 530°C 260 bar / 540 / 580°C 270 bar / 600 / 600°C 350 bar / 700 / 720°C

Intelligent Optimization: Double Reheat Technology

SRH with state-of-the-art

technology

Improvement through DRH technology

DRH with state-of-the-art

technology

47.0%

49.5%

50.2%

47.0%

SRH with state-of-the-art

technology

Improvement through 700°C

technology

SRH with 700 °C

technology

How DRH works

The steam is reheated in two loops, thus entering the different turbine modules with optimized parameters.

Benefits of DRH technology

In contrast to the 700°C technology the realization of a DRH application is based on proven technology such as existing turbine modules as well as known materials. This means maximized overall efficiency with modest investment costs at a high level of profitability and controllable risks.

Expertise based on experience

Siemens DRH technology has a long track record, stretch-ing from the very first projects in the 1960s to the latest state-of-the-art solutions. Today Siemens provides appli-cations which can be used in steam power plants with an output up to 1350 MW.

Siemens is tackling the issue of steam power plant efficiency optimization: DRH technology is one smart step towards achieving 50% efficiency.

DRH technology vs. 700°C technology

2.5%

3.2%

Performance Counts: Application Range for DRH Technology

The tandem-compound configuration

For smaller power output values the tandem-compound configuration will apply. In this solution all modules are mounted on one turbine-generator train. This configura-tion needs only one electrical generator.

Application Range for DRH Technology

Siemens DRH technology: benefits at a glance

• Increasing efficiency up to 49.5% • Optimal use of resources• Consistent reduction of CO2 emissions• Lower operating risk compared to 700°C technology• Compliance with highest safety standards

Siemens DRH technology is the optimal solution for applications used in steam power plants with an output between 600 and 1350 MW. The double reheating of steam can be realized in two different ways.

Application range for DRH technology

DRH applications can be used in steam power plants with an output between 600 and 1350 MW.

HP turbine

Combined axial thrust and radial journal bearing

600 MW 1000 MW

Tandem-compound configuration

* Third low-pressure turbine for output above 1000 MW, depending on project-specific parameters

I50 L2 x 12.5 L2 x 12.5I50H80 L2 x 12.5

The cross-compound configuration

For higher power output values the cross-compound con-figuration is required. By splitting the steam turbine pack-age into two separate turbine-generator trains it reduces harmful mechanical stress on the rotor. Additional bene-fits: Increasing overall plant efficiency while at the same time reducing CO2 emissions.

Combined axial thrust and radial journal bearing

1st IP turbine

LP turbines

2nd IP turbine

1200 MW 1350 MW

Cross-compound configuration

I50H80

I50 L2 x 12.5 L2 x 12.5I50 L2 x 12.5

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Subject to change without prior notice. The information in this document contains general descriptions of the technical options available, which may not apply in all cases. The required technical options should therefore be specified in the contract.