Design Principles and Sizing Approach of Unfired Once-Through Steam Generators

2011 ◽  
Author(s):  
E. Hamid ◽  
M. Newby ◽  
P. Pilidis
Keyword(s):  
Heat Transfer ◽  
Power Systems ◽  
Heat Recovery ◽  
Power Plants ◽  
Design Principle ◽  
New Technology ◽  
Combined Cycle ◽  
Steam Generators ◽  
Scaled Model ◽  
Flow Rates

One of the key elements of increasing the thermal efficiency of a combined cycle power plant (CCPP) is to improve the design and operation of the heat recovery steam generators (HRSG) utilized in the cycle. Once-through steam generator (OTSG) is a new technology introduced for heat recovery in power systems. It eliminates boiler drums and other components of conventional HRSGs. The simplicity and compactness of an OTSG justifies its application in combined cycle power plants. This paper describes a design principle and an analytical sizing approach that will assist OTSG’s designers to achieve a good design by determining the core dimension, volume of an OTSG for given flow rates and their entering and leaving temperatures as well as the heat transfer area on the smoke side. The developed model has been tested with reference to a scaled model of an existing OTSG that is installed at Manx Electricity Authority and the results were promising. The overall characteristics of heat transfer and pressure drop distributions of the OTSG “scaled model” shows general agreement with the real characteristics of the existing OTSG with error values less than 1%.

scholarly journals Gas Turbine Heat Recovery Steam Generators for Combined Cycles Natural or Forced Circulation Considerations

1988 ◽  
Author(s):  
Akber Pasha
Keyword(s):  
Gas Turbine ◽  
Steam Generator ◽  
Heat Recovery ◽  
Power Plants ◽  
Natural Circulation ◽  
Combined Cycle ◽  
Heat Recovery Steam Generator ◽  
Steam Generators ◽  
Forced Circulation ◽  
Gas Turbine Exhaust

In recent years the combined cycle has become a very attractive power plant arrangement because of its high cycle efficiency, short order-to-on-line time and flexibility in the sizing when compared to conventional steam power plants. However, optimization of the cycle and selection of combined cycle equipment has become more complex because the three major components, Gas Turbine, Heat Recovery Steam Generator and Steam Turbine, are often designed and built by different manufacturers. Heat Recovery Steam Generators are classified into two major categories — 1) Natural Circulation and 2) Forced Circulation. Both circulation designs have certain advantages, disadvantages and limitations. This paper analyzes various factors including; availability, start-up, gas turbine exhaust conditions, reliability, space requirements, etc., which are affected by the type of circulation and which in turn affect the design, price and performance of the Heat Recovery Steam Generator. Modern trends around the world are discussed and conclusions are drawn as to the best type of circulation for a Heat Recovery Steam Generator for combined cycle application.

Study and Design of Heat Recovery Steam Generators

2002 ◽  
Author(s):  
S. Vedanth
Keyword(s):  
Power Systems ◽  
Coming Out ◽  
Heat Recovery ◽  
Power Plants ◽  
Waste Heat ◽  
Material Selection ◽  
Steam Generators ◽  
Industrial Plants ◽  
Pipe Line ◽  
Reliability Of Operation

In the modern scenario of energy systems, we see that the efficiency of the modern day power plants attain a maximum possible limit of 40%–50% in most cases. This is a result of the wastage’s that are prevalent in the systems in the form of heat loss, friction losses due to flow in pipes and flow in other units. The modern day power plants employ the Heat Recovery Steam Generators ( HRSG) which help in converting the waste heat coming out of the turbine into useful work, thus increasing the overall efficiency of the plant. The application of Gas turbine generator (GT) based co-Generation power plants as a part of the industrial plants is on the rise. These plants are required to meet the industrial plants power and steam demand with variations associated with it. This paper deals with the study of a versatile industrial HRSG with specifications in order to support the design. The study and design is based on the design and production unit “Babcock Borsig power systems”, Chennai, India. The paper focuses on the Heat recovery Steam Generator design inclusive of selecting the parameters like pressure of steam, velocity of fluids at different stages with respect to the conditions, material selection etc. The design of HRSG involves primary inputs such as the Engineering Flow diagrams, Arrangement of Equipment’s at proper elevation and Engineering data (Specifications). The considerations of line sizing with respect to pressure drop, Net positive Suction Head, Pipe line erosion, Water Hammer and noise are taken into account. A well-specified and designed HRSG can substantially help the Industrial Co-Generation plant to meet the demand variation and imbalances without sacrificing the reliability of operation. The study is an important contribution to the exponentially rising population and hence the energy demands in the world.

Modified Rankine HRSG Beats Triple-Pressure System

1996 ◽  
Author(s):  
Peter Eisenkolb ◽  
Martin Pogoreutz ◽  
Hermann Halozan
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Power Plants ◽  
Fossil Fuels ◽  
Combined Cycle ◽  
Exhaust Gas ◽  
Pressure System ◽  
Exergy Losses

Gas-fired combined cycle power plants (CCP) are presently the most efficient systems for producing electricity with fossil fuels. Gas turbines have been and are being improved remarkably during the last years; presently they achieve efficiencies of more than 38% and gas turbine outlet temperatures of up to 610°C. These high outlet temperatures require modifications and improvements of heat recovery steam generators (HRSG). Presently dual pressure HRSGs are most commonly used in combined cycle power stations. The next step seems to be the triple-pressure HRSG to be able to utilise the high gas turbine outlet temperatures efficiently and to reduce exergy losses caused by the heat transfer between exhaust gas and the steam cycle. However, such triple-pressure systems are complicated considering parallel tube bundles as well as start up operation and load changes. For that reason an attempt has been made to replace such multiple pressure systems by a modified Rankine cycle with only a single-pressure level. In the case of the same total heat transfer surfaces this innovative single-pressure system achieves approximately the same efficiency as the triple-pressure system. By optimising the heat recovery from the exhaust gas to the steam/water cycle, i.e. minimising exergy losses, the stack temperature is much higher. Increasing the heat transfer surfaces means a decrease of the stack temperature and a further improvement of the overall CCP-efficiency. Therefore one has to be aware that the proposed system offers advantages not only in the case of a foreseeable increase of gas turbine outlet temperatures but also for presently available gas turbines. Using existing highly efficient gas turbines and subcritical steam conditions, power plants with this proposed Eisenkolb Single Pressure (ESP_CCP) heat recovery steam generator achieve thermal efficiencies of about 58.7% (LHV).

An Impact of Environmental Disturbances on Combined Cycle Power Plant Control

2004 ◽  
Author(s):  
Zygfryd Domachowski ◽  
Marek Dzida
Keyword(s):  
Power Plant ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Power Plants ◽  
Ambient Pressure ◽  
Combined Cycle ◽  
Steam Generators ◽  
Environmental Disturbances ◽  
Power Plant Control ◽  
Plant Control

Combined cycle power plants operate at thermal efficiency approaching 60 percent. In the same time their performance presents several problems that have to be addressed. E.g. gas turbines are very sensitive to backpressure exerted on them by the heat recovery steam generators as well as to ambient pressure and temperature.

40 Years of Combined Cycle Power Plants

2002 ◽  
Author(s):  
Lothar Balling ◽  
Heinz Termuehlen ◽  
Ray Baumgartner
Keyword(s):  
Power Generation ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Power Plants ◽  
Combined Cycle ◽  
Steam Generators

Even though the first installations of combined cycle power plants with heat recovery steam generators (HRSG’s) are only about forty years old, the first attempt to build gas turbines for power generation was made more than 100 years ago. It took however about 40 years before gas turbines were installed to supply peaking power.

Water/Steam Treatment Programs and Chemistry Control for Heat Recovery Steam Generators

2013 ◽  
Author(s):  
Brad Buecker
Keyword(s):  
Heat Recovery ◽  
Power Plants ◽  
High Reliability ◽  
Combined Cycle ◽  
Steam Treatment ◽  
Steam Turbines ◽  
Steam Generators ◽  
Accelerated Corrosion ◽  
Boiler Water ◽  
Water Steam

New power generation in the U.S. is being dominated by installation of combined-cycle power plants, where a significant portion of the power is produced from steam turbines supplied by heat recovery steam generators (HRSG). Proper chemistry control and monitoring of HRSG feedwater, boiler water, and steam are essential for high reliability and availability of these units. However, many plants have minimal staff, most if not all of whom have no formal chemistry training and who may not fully understand the importance of water/steam chemistry and monitoring techniques. This paper provides an outline of the most important chemistry control methods and also examines the phenomenon of flow-accelerated corrosion (FAC). FAC is the leading cause of corrosion in HRSGs,[1] and is often the result of the outdated belief that oxygen scavengers are a requirement for feedwater treatment. Since 1986, FAC-induced failures at several coal-fired power plants have killed or injured a number of U.S. utility workers.

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