BENSON Boiler Technology Leading boiler manufacturers construct BENSON boilers worldwide under Siemens license. The success of the technology is based on highest economy in power plant operation by High efficiency due to high steam parameters Flexible operation in sliding pressure mode Based on extensive experience and on basic research and development the Siemens BENSON test rig highest reliability of BENSON boilers is assured. Modern boilers are characterized by three essential features. All of them have been introduced by Siemens: Once-through principle Supercritical steam pressure Variable pressure operation Copyright Siemens AG 2009. All rights reserved. 1
BENSON HRSG The BENSON Low Mass Flux Design Principle developed for coal fired steam generators and patented by Siemens was successfully applied for an Once-Through Heat Recovery Steam Generator (HRSG) at the Cottam 390MW CCPP in Great Britain in 1999. Leading HRSG manufacturers worldwide have obtained licenses for this technology from Siemens. Copyright Siemens AG 2009. All rights reserved. 2
Research & Development The high reliability is based on scientifically founded design fundamentals and experiences: Intensive research and development especially in the field of heat transfer and pressure drop of two phase flow at the Siemens BENSON test rig Continuous exchange of information between Siemens, the BENSON licensees and customers as well BENSON test rig in Erlangen Copyright Siemens AG 2009. All rights reserved. 3
BENSON Boiler Heat Transfer and Pressure Drop in Tubes Siemens BENSON Boiler research has established the world's largest database for heat transfer and pressure drop in tubes. Flexibility Features A coal fired power plant with BENSON Boiler can sustain load transients of 4 to 6% per min over a wide load range and in sliding pressure mode. Copyright Siemens AG 2009. All rights reserved. 4
BENSON Boiler: Operation Mode of Power Plants Operation Mode of Power Plants Sliding pressure is an essential requirement to reduce thermal stresses in the turbine. The size and geometry of the furnace of a BENSON boiler can be optimally matched to the fuel with no restrictions on the water/steam side, because the transition from evaporation to superheating is not fixed in location. Copyright Siemens AG 2009. All rights reserved. 5
Firing Concepts for BENSON Boilers The BENSON boiler is constructed with the widest possible range of firing systems. Copyright Siemens AG 2009. All rights reserved. 6
Efficiency BENSON: Net Efficiency Increase of Efficiency The most effective measure for achieving high power plant efficiency is selecting high steam pressure and high steam temperature. Increasing the steam pressure from 167 bar, the standard for drum boilers, to 250 bar enhances the Copyright Siemens AG 2009. All rights reserved. 7
efficiency by roughly 3% without significant increases in investment costs. The design concept of BENSON Boilers is independent of subcritical and supercritical steam pressure. BENSON Boilers have been built to date for pressures up to 310 bar and temperatures up to 650 C. Copyright Siemens AG 2009. All rights reserved. 8
Licensees BENSON technology is available everywhere, as leading boiler manufacturers in all parts of the world have obtained licenses from Siemens. Copyright Siemens AG 2009. All rights reserved. 9
The Licensees use the comprehensive BENSON know-how based on continuous research and development and global exchange of information. The Siemens know-how of interaction between boiler, turbine and other major components as the basis for cost-effective and reliable power plant operation completes the BENSON technology experience. Copyright Siemens AG 2009. All rights reserved. 10
History of BENSON Technology Based on the concept developed by Mark Benson, Siemens continued to develop this type of boiler in the mid twenties while retaining the name BENSON Boiler. It was recognized that a once-through evaporator could be operated at both subcritical and supercritical pressure. Copyright Siemens AG 2009. All rights reserved. 11